用简便方法计算下面各题。(1)1.25×7.9×0.8(2)6.2×9.9(3)6.8×19+6.8(4)7.2×5.8+7.2×4.2-五年级数学
(1)1.25×7.9×0.8 =1.25×0.8×7.9 =1×7.9 =7.9(2)6.2×9.9 =6.2×10-6.2×0.1 =62-0.61 =61.38(3)6.8×19+6.8 =6.8×(19+1) =6.8×20 =136(4)7.2×5.8+7.2×4.2 =7.2×(5.8+4.2) =7.2×10 =72
题目简介
用简便方法计算下面各题。(1)1.25×7.9×0.8(2)6.2×9.9(3)6.8×19+6.8(4)7.2×5.8+7.2×4.2-五年级数学
题目详情
答案
=1.25×0.8×7.9
=1×7.9
=7.9
=6.2×10-6.2×0.1
=62-0.61
=61.38
=6.8×(19+1)
=6.8×20
=136
=7.2×(5.8+4.2)
=7.2×10
=72