Question

2.7×10.2-9.8×2.5的简便运算？

Answer 1

=(2.5+0.2)×10.2－9.8×2.5
=2.5×10.2+10.2×0.2－9.8×2.5
=2.5×(10.2－9.8)+10.2×0.2
=2.5×0.4+10.2×0.2
=2.5×2×0.2+10.2×0.2
=0.2×(5+10.2)
=0.2×15.2
=0.1×2×15.2
=3.04

Answer 2

解:运用乘法分配律，将10.2化为10+0.2与2.7分别相乘，将9.8化为10-0.2与2.5分别相乘，然后按四则运算法则进行计算。计算过程
2.7ⅹ10.2-9.8ⅹ2.5
=2.7x(10+0.2)-(10-0.2)ⅹ2.5
=27+0.54-25-0.5
=2.04。