500+50-40+30-20+80-70+60-50+40-30=?
问题描述:
500+50-40+30-20+80-70+60-50+40-30=?
答
500+10*5=550
答
500+50-40+30-20+80-70+60-50+40-30=550
答
500+260-210=550