= 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 lbs (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)

= 1x 1

= 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、9 123-( 123+8.8)

=9 123- 123-8.8

=9000-8.8

=899 1.2