简便计算: 2.4×99 , 3.19×7.85+1.15×3.19+3.19
问题描述：
简便计算: 2.4×99 , 3.19×7.85+1.15×3.19+3.19
答
你好！
2.4×99
=2.4×（100-1）
=2.4×100-2.4×1
=240-2.4
=237.6
3.19×7.85+1.15×3.19+3.19
=3.19×7.85+1.15×3.19+3.19×1
=（1.15+7.85+1）×3.19
=10×3.19
=31.9
祝你学习进步，望采纳，谢谢！O(∩_∩)O~
答
2.4×99=2.4x(100-1)=240-2.4=237.6
3.19×7.85+1.15×3.19+3.19=3.19x(7,85+1.15+1)=3.19x10=31.9
答
2.4*(100-1)
=2.4*100-2.4*1
=237.6
3.19*7.85+1.15*3.19+3.19
=3.19*7.85+3.19*1.15+3.19*1
=3.19*(7.85+1.15+1)
=31.9