数学简便运算:4.2×4.2+0.42×58

问题描述:

数学简便运算:4.2×4.2+0.42×58

4.2×4.2+0.42×58
=4.2×4.2+4.2×5.8
=4.2×(4.2+5.8)
=4.2×10
=42