Question

四点8×0点五二乘法验算？

Answer 1

四点8×0点五二，即4.8*0.52=2.496。
验算过程是：2.496÷4.8=0.52；2.496÷0.52=4.8。

Answer 2

4.8*0.52=4.8*5.2*9.1
=(5-0.2)(5+0.2)*0.1
=(5^2-0.2^2)*0.1
=(25-0.04)*0.1
=2.496
验算：新不考虑小数点，被乘数弃九=3，乘数弃九=7，乘积弃九=3,3*7的积弃九=3，正确
被乘数小数位=1，成熟小数位=2，乘积小数位=3,1+2=3，正确。∴运算正确

Answer 3

解：4.8×0.52
＝（5-0.2）×0.52
＝5×0.52-0.2×0.52
＝2.6-0.104
＝2.496
验算是：
2.496÷4.8＝0.52，所以正确。

Answer 4

4.8×0.52
=（5-0.2）×0.52
=5×0.52-0.2×0.52
=2.6-0.104
=2.496