(1/7-1/9)×6.3+2/5简便计算帮帮忙

问题描述:

(1/7-1/9)×6.3+2/5简便计算帮帮忙

(1/7-1/9)x6.3+2/5=1/7x6.3-1/9x6.3+0.4=0.9-0.7+0.4=0.6