运算定律和简便算法问题大全及答案
更新时间:2021-06-23
类型:小学五年级数学题
题数:99
答:
3x×5x=(3+5)×x.故答案为:3、5、x.
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答:
2.9×0.35+0.29×4.5+0.029×20=2.9×0.35+2.9×0.45+2.9×0.2=2.9×(0.35+0.45+0.2)=2.9×1=2.9.
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答:
2005×20062006-2006×20052005,=2005×2006×10001-2006×2005×10001,=0;故答案为:0.
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答:
(1)4.2×4.2+4.2×5.8,=4.2×(4.2+5.8),=4.2×10,=42;(2)0.89×99,=0.89×(100-1),=0.89×100-0.89×1,=89-0.89,=88.11.
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答:
(1)(2.5+3.5)×4,=6×4,=24;(2)2.5×28,=2.5×4×7,=10×7,=70.
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答:
88.88×33.34+44.44×33.32=44.44×2×33.34+44.44×33.32=44.44×(2×33.34)+44.44×33.32=44.44×66.68+44.44×33.32=44.44×(66.68+33.32)=44.44×100=4444.
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答:
9.04×101=9.04×(100+1)=9.04×100+9.04=904+9.04=913.04;故答案为:9.04.
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答:
(5+x)×b=5×b+x×b.故答案为:5、b、x、b.
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答:
(1)原式=3+1-3 =1(2)原式=++- =+ =(3)原式=-(+) =-1 =(4)原式=-- =1- =
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答:
80×1.6×2.5×1.25=(80×1.25)×(1.6×2.5)=100×(4×0.4×2.5)=100×4=400.故答案为:400.
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答:
8.9×0.99=8.9×(1-0.01)=8.9-8.9×0.01=8.9-0.089=8.811.故答案为:√.
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答:
4.65×32+2.5×46.5+0.465×430=4.65×32+25×4.65+4.65×43=4.65×(32+25+43)=4.65×100=465.
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答:
2b×(b+c)=2b2+2bc,故答案为:错误.
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答:
l.68×3.75×160.24+1.25×4.96×160.24.=160.24×(1.68×3.75+1.25×4.96)=160.24×(6.3+6.2)=160.24×12.5=2003
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答:
7.836×3.40+3.34×2.384+3.69×7.836=7.836×3.40+3.69×7.836+3.34×2.384=7.836×(3.40+3.69)+3.34×2.384=7.836×3.34+3.34×2.384=3.34×(7.836+2.384)=3.34×30=33.4;故答案为33.4.
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答:
根据乘法分配律可知,413×9+9×913=9×(413+913) 是正确4.故答案为:√.
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