1.25乘8.88
=1.25*8*1.11
=10*1.11
=11.1
9.8乘4.7+9.8+6.3乘9.8
=9.8*（4.7+1+6.3）
=9.8*12
=（10-0.2）*12
=10*12-0.2*12
=120-2.4
=117.6
（0.69乘99+0.69）除以0.23
=0.69*（99+1）/0.23
=0.69*100/0.23
=69/0.23
=300
7.64-（6.9-0.6乘0.6）
=7.64+0.36-6.9
=8-6.9
=1.1