□○□=□(根)
56+20-8=
33+8-40=
35-6+30=
24-(17-8)=
6+(87-30)=
80-7+20=
8+43+9=
15+(22+8)=
3+40+9=
76-70+56=
37+(17-8)=
81-8+20=
2×4= 8×5= 7×6= 5×1=
6×3+12= 5×6-13= 40-3×4= 28+4×6=
16+8= 30-6= 35-19-8= 5×6+7=
60-20=
5×9=
36+4=
57+8=
76-40=
8×4=
7×5=
70-7=
9×9=
6×5=
2×7=
53-8=
26+30-5=
12-3×2=
7×9+3=
89-32-7=
口诀:
(个)
或(个)
0.45×0.8 = 5.6÷10 =