3.5×5／4＋1.25＋3／2÷4／5
=3.5×5/4+1.25+1.5×5/4
=5/4×(3.5+1.5)+1.25
=6.25+1.25
=7.5
12.5×﹙36－36／5﹚÷3.6
=12.5×(1-1/5)×36÷3.6
=12.5×4/5×10
=12.5×8
=100
20／3÷﹙22／5－56／15﹚×0.9
=20/3÷[1/5×(22-56/3)]×9/10
=20/3÷[1/5×(66/3-56/3)]×9/10
=20/3÷(1/5×1/3)×9/10
=20/3×15×9/10
=90
﹙5／25＋5／25×3﹚×0.25
=(1+3)×5/25×1/4
=4×1/5×1/4
=1/5