Question

小数加法和减法的简便计算

Answer 1

1、1.25×(8+10)

=1.25×8+1.25×10

=10+12.5

=22.5

2、1.24+0.78+8.76

=(1.24+8.76)+0.78

=10+0.78

=10.78

3、1/2-(4/5-1/2)

=1/2+1/2-4/5

=1-4/5

=1/5

4、4800÷25÷4

=4800÷(25x4)

=4800÷100

=4800÷100

=48

5、2/5-(3/8-3/5)

=2/5+3/5-3/8

=1-3/8

=5/8

6、3/4-(3/7-1/4)

=3/4+1/4-3/7

=1-3/7

=4/7

7、3.2x0.125x2.5

=0.125x8x(0.4x2.5)

=1x1

=1

8、0.4×125×25×0.8

=(0.4×25)×(125×0.8)

=10×100

=1000

9、1.25×(8+10)

=1.25×8+1.25×10

=10+12.5

=22.5

10、9123-(123+8.8)

=9123-123-8.8

=9000-8.8

=8991.2