二、解决问题
★信息窗 2-4
建议用时:6分钟
实际用时:分钟
20-7 =
46-6 =
4×2 =
9×3 =
5×9 =
7×2 =
48÷8 =
90-8 =
66÷7 =
66-40 =
20+47 =
56+16 =
33+17 =
86-60 =
20+80 =
32÷4 =
40÷6 =
43÷7 =
81÷9 =
67÷8 =
25-9 =
6+38 =
43-20 =
88+9 =
30+70 =
210+150 =
16+51 =
50+210 =
16+150 =
120+370 =
100-90 =
15+60 =
78-8 =
50-2 =
26+40 =
3+46 =
58-7 =
30+45 =
260-160+90 =
420+123-143 =
240+170 =
580-200 =
29+800 =
320+180 =
940-320 =

20-7 = 13
46-6 = 40
4×2 = 8
9×3 = 27
5×9 = 45
7×2 = 14
48÷8 = 6
90-8 = 82
66÷7 = 9……3
66-40 = 26
20+47 = 67
56+16 = 72
33+17 = 50
86-60 = 26
20+80 = 100
32÷4 = 8
40÷6 = 6……4
43÷7 = 6……1
81÷9 = 9
67÷8 = 8……3
25-9 = 16
6+38 = 44
43-20 = 23
88+9 = 97
30+70 = 100
210+150 = 360
16+51 = 67
50+210 = 260
16+150 = 166
120+370 = 490
100-90 = 10
15+60 = 75
78-8 = 70
50-2 = 48
26+40 = 66
3+46 = 49
58-7 = 51
30+45 = 75
260-160+90 = 190
420+123-143 = 400
240+170 = 410
580-200 = 380
29+800 = 829
320+180 = 500
940-320 = 620

下图中共有几个长方形？

4+2+1+1=8（个）
答：共有8个长方形。