（1）7.8×11-7.8

=7.8×(11-1)

=78

（2）1.25×3.2×0.25

=(1.25×8)×(0.4×0.25)

=10×0.1

=1

（3）9.05-24.12÷3.6

=9.05-6.7

=2.35

（4）4.3×1.02

=4.3×(1+0.02)

=4.3×1+4.3×0.02

=4.3+0.086

=4.386