Question

7.8➕990✖️0.78的简便计算？

Answer 1

7.8+990X0.78
=0.78X10+990X0.78
=0.78X(10+990)
=0.78X1000
=780

Answer 2

7.8+990×0.78简便计算？
解:原式=0.78×10+990×0.78
=0.78×(990+10)
=0.78×1000
=780
运用乘法结合律计算。

Answer 3

7.8+990×0.78
=7.8+99×7.8
=7.8×(99+1)
=7.8×100
=780