1. 直接写得数。

13–8 =  17–3 =22+5 =60+23 –3=

43+ 20=7+60=68– 6=88– 50+30 =

88–7 = 6+9 =13－9=75–60+70=

90–20=  50+48 = 74–40 =78–8–30 =

49+ 40=15–8= 30+60 =32+50–40 =