1.4乘七分之五
=7/5×5/7
=1
1.5乘五分之四
=3/2×4/5
=6/5
四分之三除以0.25
=3/4×4
=3
1.5除以1.7
=15÷17
=15/17
四分之一减1.2
=0.25-1.2
=-0.95
1.3除以1.4
=13÷14
=13/14