Question

下面计算的对吗?对的打对,不对的请改正.

Answer 1

1 错 2 错 3 对 4错

1订2.5×7.5×0.5

=2.5×4×2×7.5×0.5/（2×4）

=10×1×7.5/8

=75/8

=9.375

2订8.5×99

=8.5×（100-1）

=8.5×100-8.5×1

=850-8.5

=841.5

4订1.25×(8+0.8)

=1.25×8+1.25×0.8

=10+1

=11