124.68+324.68+524.68+724.68+924.68=______.
问题描述:
124.68+324.68+524.68+724.68+924.68=______.
答
124.68+324.68+524.68+724.68+924.68
=(100+24+0.6+0.08)+(300+24+0.6+0.08)+(500+24+0.6+0.08)+(700+24+0.6+0.08)+(900+24+0.6+0.08)
=(100+300+500+700+900)+(24+24+24+24+24)+(0.6+0.6+0.6+0.6+0.6)+(0.08+0.08+0.08+0.08+0.08)
=[(100+900)+(300+700)+500]+24×5+0.6×5+0.08×5
=[1000+1000+500]+120+3+0.4
=2500+120+3+0.4
=2620+3+0.4
=2623+0.4
=2623.4.
故答案为:2623.4.
答案解析:根据加法交换律和结合律进行简算.
考试点:运算定律与简便运算.
知识点:完成本题要注意分析式中数据,运用合适的简便方法计算.