{5又9分之5减去0.8+2又9分之4}乘以{7.6除以5分之4+2又5分之4乘以1.25},等于?

{5又9分之5减去0.8+2又9分之4}乘以{7.6除以5分之4+2又5分之4乘以1.25}
={5又9分之5+2又9分之4-0.8}×{7.6×5/4+2又5分之4×5/4}
=7.2×{(7.6+2又5分之4)×5/4}
=7.2×13
=93.6
题目是否打错,应该是:
5又9分之5减去0.8+2又9分之4}乘以{7.2除以5分之4+2又5分之4乘以1.25}
={5又9分之5+2又9分之4-0.8}×{7.2×5/4+2又5分之4×5/4}
=7.2×{(7.2+2.8)×5/4}
=7.2×10×5/4
=90没打错，谢谢