题目内容
怎样算简便就怎样算
350×[(120-60)÷15] | 125×25×32 | [285-(15+20)]×3 | 23×199+23 |
203×199 | (80+4)×25 | 72×5+72×4+72 | 34×72+34×28. |
考点:整数四则混合运算,运算定律与简便运算
专题:运算顺序及法则,运算定律及简算
分析:(1)先算小括号里面的减法,再算中括号里面的除法,最后算括号外的乘法;
(2)先把32分解成8×4,再根据乘法交换律和结合律简算;
(3)先算小括号里面的加法,再算中括号里面的减法,最后算括号外的乘法;
(4)(6)(7)(8)根据乘法分配律简算;
(5)先把199分解成(200-1),再运用乘法分配律简算.
(2)先把32分解成8×4,再根据乘法交换律和结合律简算;
(3)先算小括号里面的加法,再算中括号里面的减法,最后算括号外的乘法;
(4)(6)(7)(8)根据乘法分配律简算;
(5)先把199分解成(200-1),再运用乘法分配律简算.
解答:
解:(1)350×[(120-60)÷15]
=350×[60÷15]
=350×4
=1400;
(2)125×25×32
=125×25×(8×4)
=(125×8)×(25×4)
=1000×100
=100000;
(3)[285-(15+20)]×3
=[285-35]×3
=250×3
=750;
(4)23×199+23
=23×(199+1)
=23×200
=4600;
(5)203×199
=203×(200-1)
=203×200-203×1
=40600-203
=40397;
(6)(80+4)×25
=80×25+4×25
=2000+100
=2100;
(7)72×5+72×4+72
=72×(5+4+1)
=72×10
=720;
(8)34×72+34×28
=34×(72+28)
=34×100
=3400.
=350×[60÷15]
=350×4
=1400;
(2)125×25×32
=125×25×(8×4)
=(125×8)×(25×4)
=1000×100
=100000;
(3)[285-(15+20)]×3
=[285-35]×3
=250×3
=750;
(4)23×199+23
=23×(199+1)
=23×200
=4600;
(5)203×199
=203×(200-1)
=203×200-203×1
=40600-203
=40397;
(6)(80+4)×25
=80×25+4×25
=2000+100
=2100;
(7)72×5+72×4+72
=72×(5+4+1)
=72×10
=720;
(8)34×72+34×28
=34×(72+28)
=34×100
=3400.
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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