Bài tập cơ bản bài Quy tắc dấu ngoặc

Home Lớp 6 Toán lớp 6 sách cũ Quy tắc dấu ngoặc

{"segment":[{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["18","+18"]]],"list":[{"point":5,"width":60,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop6/toan/daiso/bai24/lv1/img\/2.jpg' \/><\/center>(-35) + 7 + 11 + 35 = _input_","hint":"","explain":"H\u01b0\u1edbng d\u1eabn:<\/span><br\/> Thay \u0111\u1ed5i v\u1ecb tr\u00ed s\u1ed1 h\u1ea1ng v\u00e0 b\u1ecf ho\u1eb7c \u0111\u1eb7t d\u1ea5u ngo\u1eb7c m\u1ed9t c\u00e1ch th\u00edch h\u1ee3p r\u1ed3i t\u00ednh<br\/>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}(-35) + 7 + 11 + 35 &= -35 + 7 + 11 + 35 \\\\&= (35 - 35) + (7 + 11)\\\\&= 0 + 18\\\\&= 18\\end{align*}$<br\/>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0: 18<\/span><\/span> <br\/> "}]}],"id_ques":1141},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["-20"]]],"list":[{"point":5,"width":60,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop6/toan/daiso/bai24/lv1/img\/2.jpg' \/><\/center>(-8) + 110 + (-12) + (-110) = _input_","hint":"","explain":"H\u01b0\u1edbng d\u1eabn:<\/span><br\/> Thay \u0111\u1ed5i v\u1ecb tr\u00ed s\u1ed1 h\u1ea1ng v\u00e0 b\u1ecf ho\u1eb7c \u0111\u1eb7t d\u1ea5u ngo\u1eb7c m\u1ed9t c\u00e1ch th\u00edch h\u1ee3p r\u1ed3i t\u00ednh.<br\/>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}(-8) + 110 + (-12) + (-110) &= [(-8) + (-12)] + [110 + (-110)]\\\\&= -20 + 0\\\\&= -20\\end{align*}$<br\/>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0: -20<\/span><\/span> <br\/> "}]}],"id_ques":1142},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" \u0110\u01a1n gi\u1ea3n bi\u1ec3u th\u1ee9c: x + 12 + (-34) + (-12)","select":["A. x - 34","B. x - 46","C. x - 82","D. x + 34"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u1ecf d\u1ea5u ngo\u1eb7c r\u1ed3i th\u1ef1c hi\u1ec7n t\u00ednh<br\/>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}x + 12 - 34 - 12 &= x + (12 - 12 - 34)\\\\&= x + (0 - 34) \\\\&= x - 34\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: A. x - 34<\/span><\/span> <br\/>","column":2}]}],"id_ques":1143},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":" \u0110\u01a1n gi\u1ea3n bi\u1ec3u th\u1ee9c: x - (32 + x) + 100 + x","select":["A. x + 132","B. x + 68","C. 3x + 68","D. 3x + 132"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u1ecf d\u1ea5u ngo\u1eb7c r\u1ed3i th\u1ef1c hi\u1ec7n t\u00ednh<br\/>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}x - (32 + x) + 100 + x &= x - 32 - x + 100 + x\\\\&= x + (x - x) + (100 - 32)\\\\&= x + 0 + 68\\\\&= x + 68\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: B. x + 68<\/span><\/span> <br\/>","column":2}]}],"id_ques":1144},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["-138"]]],"list":[{"point":5,"width":60,"type_input":"","ques":" T\u00ednh nhanh: <br\/>(2497 - 138) - 2497 = _input_","hint":"","explain":"H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u1ecf ngo\u1eb7c r\u1ed3i nh\u00f3m c\u1eb7p s\u1ed1 c\u00f3 t\u1ed5ng ho\u1eb7c hi\u1ec7u b\u1eb1ng 0 hay l\u00e0 s\u1ed1 tr\u00f2n ch\u1ee5c, tr\u00f2n tr\u0103m, tr\u00f2n ngh\u00ecn... \u0111\u1ec3 th\u1ef1c hi\u1ec7n t\u00ednh nhanh<br\/>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}(2497 - 138) - 2497 &= 2497 - 138 - 2497 \\\\&= (2497 - 2497) - 138\\\\&= 0 - 138\\\\&= -138\\end{align*}$<br\/>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0: -138<\/span><\/span> <br\/> "}]}],"id_ques":1145},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["-965"]]],"list":[{"point":5,"width":60,"type_input":"","ques":" T\u00ednh nhanh: <br\/>(-815) - (-35 + 185) = _input_","hint":"","explain":"H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u1ecf ngo\u1eb7c r\u1ed3i nh\u00f3m c\u1eb7p s\u1ed1 c\u00f3 t\u1ed5ng ho\u1eb7c hi\u1ec7u b\u1eb1ng 0 hay l\u00e0 s\u1ed1 tr\u00f2n ch\u1ee5c, tr\u00f2n tr\u0103m, tr\u00f2n ngh\u00ecn... \u0111\u1ec3 th\u1ef1c hi\u1ec7n t\u00ednh nhanh.<br\/>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}(-815) - (-35 + 185) &= -815 + 35 - 185 \\\\&= - (815 + 185) + 35\\\\&= -1000 + 35\\\\&= - (1000 - 35)\\\\&= -965\\end{align*}$<br\/>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0: -965<\/span><\/span> <br\/> Nh\u1eadn x\u00e9t:<\/span> <br\/>Trong m\u1ed9t t\u1ed5ng \u0111\u1ea1i s\u1ed1, ta c\u00f3 th\u1ec3: \u0111\u1eb7t d\u1ea5u ngo\u1eb7c \u0111\u1ec3 nh\u00f3m c\u00e1c s\u1ed1 h\u1ea1ng m\u1ed9t c\u00e1ch t\u00f9y \u00fd v\u1edbi ch\u00fa \u00fd r\u1eb1ng n\u1ebfu tr\u01b0\u1edbc d\u1ea5u ngo\u1eb7c l\u00e0 d\u1ea5u ( - ) th\u00ec ph\u1ea3i \u0111\u1ed1i d\u1ea5u t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c<br\/>V\u00ed d\u1ee5: a - b - c = a - (b + c)<\/b><\/span><\/span> "}]}],"id_ques":1146},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":" B\u1ecf ngo\u1eb7c r\u1ed3i t\u00ednh: <br\/>(243 + 192) + (346 - 118 - 39) = ?<\/span>","select":["A. -68","B. 624","C. 246","D. 938"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u1ecf d\u1ea5u ngo\u1eb7c r\u1ed3i th\u1ef1c hi\u1ec7n t\u00ednh<br\/>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}(243 + 192) + (346 - 118 - 39) &= 243 + 192 + 346 - 118 - 39\\\\&= 435 + 346 - 118 - 39 \\\\&= 781 - 118 - 39\\\\&= 663 - 39\\\\&= 624\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: B. 624<\/span><\/span> <br\/>","column":2}]}],"id_ques":1147},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" B\u1ecf ngo\u1eb7c r\u1ed3i t\u00ednh: <br\/>(325 - 138 + 69) - (421 + 69) = ?<\/span>","select":["A. -234","B. -96","C. 608","D. 746"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u1ecf d\u1ea5u ngo\u1eb7c r\u1ed3i th\u1ef1c hi\u1ec7n t\u00ednh<br\/>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}(325 - 138 + 69) - (421 + 69) &= 325 - 138 + 69 - 421 - 69\\\\&= 69 - 69 - 138 - 421 + 325 \\\\&= 0 - (138 + 421) + 325\\\\&= - 559 + 325\\\\&= -234\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: A. -234<\/span><\/span> <br\/>","column":2}]}],"id_ques":1148},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" T\u00ecm x, bi\u1ebft:<br\/>x - (38 - 25) = 11","select":["A. x = 24","B. x = -24","C. x = -74","D. x = 74"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> + C\u00e1ch 1: <\/b><br\/>B\u01b0\u1edbc 1: T\u00ednh (38 - 25)<br\/>B\u01b0\u1edbc 2: T\u00ecm x<br\/>+ C\u00e1ch 2:<\/b><br\/>Coi (38 - 25) l\u00e0 s\u1ed1 tr\u1eeb, t\u00ecm x ( x \u1edf v\u1ecb tr\u00ed l\u00e0 s\u1ed1 b\u1ecb tr\u1eeb, mu\u1ed1n t\u00ecm s\u1ed1 b\u1ecb tr\u1eeb ta l\u1ea5y hi\u1ec7u c\u1ed9ng v\u1edbi s\u1ed1 tr\u1eeb)<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>C\u00e1ch 1:<\/b><br\/>$\\begin{align*}x - (38 - 25) &= 11\\\\x - 13&= 11 \\\\x&= 11 + 13\\\\x&= 24\\end{align*}$<br\/> C\u00e1ch 2:<\/b><br\/> $\\begin{align*}x - (38 - 25) &= 11\\\\x &= 11 + (38 - 25) \\\\x&= 11 + 13\\\\x&= 24\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: A. x = 24<\/span><\/span> <br\/><\/span>","column":2}]}],"id_ques":1149},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":" T\u00ecm x, bi\u1ebft:<br\/>38 - x = -14 + (-12)","select":["A. x = 12","B. x = -12","C. x = -64","D. x = 64"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/>B\u01b0\u1edbc 1: T\u00ednh v\u1ebf ph\u1ea3i<br\/>B\u01b0\u1edbc 2: T\u00ecm x<br\/>L\u01b0u \u00fd:<\/b> x \u1edf v\u1ecb tr\u00ed l\u00e0 s\u1ed1 tr\u1eeb, mu\u1ed1n t\u00ecm s\u1ed1 tr\u1eeb ta l\u1ea5y s\u1ed1 b\u1ecb tr\u1eeb tr\u1eeb \u0111i hi\u1ec7u<\/i><\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}38 - x &= -14 + (-12)\\\\38 - x&= -26 \\\\x&= 38 - (-26)\\\\x&= 38 + 26\\\\x&= 64\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: D. x = 64<\/span><\/span> <br\/>","column":2}]}],"id_ques":1150},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" T\u00ecm x, bi\u1ebft:<br\/>x + 12 = 15 - (-1)","select":["A. x = 4","B. x = -4","C. x = 28","D. x = -28"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/>B\u01b0\u1edbc 1: T\u00ednh v\u1ebf ph\u1ea3i<br\/>B\u01b0\u1edbc 2: T\u00ecm x ( x \u1edf v\u1ecb tr\u00ed l\u00e0 s\u1ed1 h\u1ea1ng, mu\u1ed1n t\u00ecm s\u1ed1 h\u1ea1ng ch\u01b0a bi\u1ebft ta l\u1ea5y t\u1ed5ng tr\u1eeb \u0111i s\u1ed1 h\u1ea1ng \u0111\u00e3 bi\u1ebft) <\/i><\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}x + 12 &= 15 - (-1)\\\\x + 12&= 15 + 1 \\\\x +12&= 16\\\\x&= 16 - 12\\\\x&= 4\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: A. x = 4<\/span><\/span> <br\/>","column":2}]}],"id_ques":1151},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":" Bi\u1ec3u th\u1ee9c a - (b + c) - d sau khi b\u1ecf ngo\u1eb7c l\u00e0:","select":["A. a - b + c - d","B. a - b - c - d","C. a + b + c - d","D. a + b - c - d"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> a - (b + c) - d = a - b - c - d<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: B. a - b - c - d<\/span><\/span> <br\/>","column":2}]}],"id_ques":1152},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":" Bi\u1ec3u th\u1ee9c (a + b) - (c - d) sau khi b\u1ecf ngo\u1eb7c l\u00e0:","select":["A. a + b - c - d","B. a + b + c + d","C. a + b - c + d","D. a + b + c - d"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3:<br\/> (a + b) - (c - d) = a + b - c + d<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: C. a + b - c + d<\/span><\/span> <br\/>","column":2}]}],"id_ques":1153},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":" Bi\u1ec3u th\u1ee9c (a - b) - (c - d) sau khi b\u1ecf ngo\u1eb7c l\u00e0:","select":["A. a - b - c - d","B. a - b + c + d","C. a - b - c + d","D. -a + b + c - d"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3:<br\/> (a - b) - (c - d) = a - b - c + d<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: C. a - b - c + d<\/span><\/span> <br\/>","column":2}]}],"id_ques":1154},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" H\u00e3y ch\u1ecdn c\u00e2u \u0111\u00fang:","select":["A. 37 - (-15 + 42) = 10","B. 84 - (15 - 36) = 33","C. 39 + (47 - 15) = 101","D. 120 - (-38) + 11 = 93"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> $\\begin{align*}37 - (-15 + 42) &= 37 - (42 - 15)\\\\&= 37 - 27 \\\\&= 10\\end{align*}$<br\/>$\\begin{align*}84 - (15 - 36) &= 84 - 15 + 36\\\\&= 69 + 36 \\\\&= 105\\end{align*}$<br\/>$\\begin{align*}39 + (47 - 15) &= 39 + 32\\\\&= 71\\end{align*}$<br\/>$\\begin{align*}120 - (-38) + 11 &= 120 + 38 + 11\\\\&= 158 + 11 \\\\&= 169\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: A. 37 - (-15 + 42) = 10<\/span><\/span> <br\/><\/span>","column":2}]}],"id_ques":1155},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":" H\u00e3y ch\u1ecdn c\u00e2u \u0111\u00fang:","select":["A. -47 + (38 - 15) = 6","B. 12 - [47 + (-18)] = -53","C. -91 + (84 - 15) = 8","D. 38 - 19 - (-11) = 30"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> $\\begin{align*}-47 + (38 - 15) &= -47 + 23\\\\&= - (47 - 23) \\\\&= -24\\end{align*}$<br\/>$\\begin{align*}12 - [47 + (-18)] &= 12 - (47 - 18)\\\\&= 12 - 29 \\\\&= - (29 - 12)\\\\&= -17\\end{align*}$<br\/>$\\begin{align*}-91 + (84 - 15)&= -91 + 69\\\\&= -(91 - 69)\\\\&= -22\\end{align*}$<br\/>$\\begin{align*}38 - 19 - (-11) &= 19 - (-11)\\\\&= 19 + 11 \\\\&= 30\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: D. 38 - 19 - (-11) = 30<\/span><\/span> <br\/><\/span>","column":2}]}],"id_ques":1156},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c A = 124 + a + b t\u1ea1i a = -38; b = -24 l\u00e0:","select":["A. 62","B. -62","C. 138","D. -138"],"hint":"Thay gi\u00e1 tr\u1ecb c\u1ee7a a v\u00e0 b v\u00e0o bi\u1ec3u th\u1ee9c A r\u1ed3i t\u00ednh ","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u01b0\u1edbc 1: Thay gi\u00e1 tr\u1ecb c\u1ee7a a v\u00e0 b v\u00e0o bi\u1ec3u th\u1ee9c A<br\/>B\u01b0\u1edbc 2: T\u00ednh gi\u00e1 tr\u1ecb bi\u1ec3u th\u1ee9c<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> Thay a = -38; b = -24 v\u00e0o bi\u1ec3u th\u1ee9c A ta \u0111\u01b0\u1ee3c:<br\/>$\\begin{align*}A &= 124 + (-38) + (-24)\\\\&= 124 - 38 - 24 \\\\&= 124 - 24 - 38\\\\&= 100 - 38\\\\&= 62\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: A. 62<\/span><\/span> <br\/>","column":2}]}],"id_ques":1157},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":" Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c A = -83 - a - b t\u1ea1i a = -15; b = 47 l\u00e0:","select":["A. 21","B. -21","C. 115","D. -115"],"hint":"Thay gi\u00e1 tr\u1ecb c\u1ee7a a v\u00e0 b v\u00e0o bi\u1ec3u th\u1ee9c A r\u1ed3i t\u00ednh ","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u01b0\u1edbc 1: Thay gi\u00e1 tr\u1ecb c\u1ee7a a v\u00e0 b v\u00e0o bi\u1ec3u th\u1ee9c A<br\/>B\u01b0\u1edbc 2: T\u00ednh gi\u00e1 tr\u1ecb bi\u1ec3u th\u1ee9c<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/> Thay a = -15; b = 47 v\u00e0o bi\u1ec3u th\u1ee9c A ta \u0111\u01b0\u1ee3c:<br\/>$\\begin{align*}A &= -83 - (-15) - 47\\\\&= -83 + 15 - 47 \\\\&= - (83 + 47 - 15)\\\\&= -(130 - 15)\\\\&= -115\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: D. -115<\/span><\/span> <br\/>","column":2}]}],"id_ques":1158},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop6/toan/daiso/bai24/lv1/img\/2.jpg' \/><\/center>-(a - b) = -a + b. \u0110\u00fang hay sai?","select":["A. \u0110\u00fang","B. Sai"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: <br\/> - (a - b) = -a + b<\/b><br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n: A. \u0110\u00fang<\/span><\/span> <br\/>","column":2}]}],"id_ques":1159},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop6/toan/daiso/bai24/lv1/img\/2.jpg' \/><\/center>-(a + b) = -a + b. \u0110\u00fang hay sai?","select":["A. \u0110\u00fang","B. Sai"],"hint":"","explain":" H\u01b0\u1edbng d\u1eabn:<\/span><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: <br\/> - (a + b) = -a - b<\/b><br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n: B. Sai<\/span><\/span> <br\/>","column":2}]}],"id_ques":1160}],"lesson":{"save":0,"level":1}}

Em chưa làm xong câu này