1.25×0.25×8×40用简便方法计算 5.7×9.9 0.34×10.1

题目

1.25×0.25×8×40用简便方法计算 5.7×9.9 0.34×10.1
1.25×0.25×8×40用简便方法计算
5.7×9.9 0.34×10.1 12.5×(10+0.8)
44.5×3.7+6.3×44.5

答案

1.25×0.25×8×40
=(1.25×8)×(0.25×40)
=10×10
=100
5.7×9.9
=5.7×(10-0.1)
=5.7×10-5.7×0.1
=57-0.57
=56.43
0.34×10.1
=0.34×(10+0.1)
=0.34×10+0.34×0.1
=3.4+0.034
=3.434
12.5×(10+0.8)
=12.5×10+12.5×0.8
=125+10
=135
44.5×3.7+6.3×44.5
=44.5×(3.7+6.3)
=44.5×10
=445