解:七点五乘以八分之五加上二点五除以五分之八等于( 25/4 ),【即等于6.25】
∵已知需求出七点五乘以八分之五加上二点五除以五分之八等于多少
∴七点五乘以八分之五加上二点五除以五分之八
= 7.5 × 5/8 + 2.5 ÷ 8/5
= (7×10+5)/10 × 5/8 + (2×10+5)/10 × 5/8
= 75/10 × 5/8 + 25/10 × 5/8
= 5/8 × (75/10 + 25/10)
= 5/8 × 100/10
= 5/8 × 10
= 25/4
= 6.25
答:七点五乘以八分之五加上二点五除以五分之八等于25/4,【即等于6.25】