7+8=
15-7=
15-8=
7+= 16
16-=
五十二是由个十和个一组成的;
我也能知道:
50+= 52-= -=
6.5+2.5= 1.23÷3= 5.2×5= 7÷14%=
= ﹣= ×= 0÷2022=
13.4﹣7.7= = = 299×5≈