四、解决问题
★信息窗 2-2
建议用时:6分钟
实际用时:分钟
37+42 =
90-37 =
70÷8 =
760-400 =
370+40 =
620+40 =
960-30 =
250+40 =
1200+400 =
4000-300 =
5×4 =
9×3 =
5×3 =
46÷5 =
3×2 =
1×4 =
81÷9 =
5×6 =
6÷3 =
5×1 =
42÷7 =
270+400 =
52+29 =
900-300 =
300+500 =
510-70 =
760+30 =
42+36 =
700-200 =
7000-3000 =
70+320 =
740-60 =
400+600 =
100-60 =
300+700 =
32+65 =
700-300 =
640-60 =
930-300 =
3000+600 =
65÷7 =
75÷9 =
81÷9 =
65÷8 =
32÷7 =

$37+42=79$
$90-37=53$
$70÷8=8······6$
$760-400=360$
$370+40=410$
$620+40=660$
$960-30=930$
$250+40=290$
$1200+400=1600$
$4000-300=3700$
$5×4=20$
$9×3=27$
$5×3=15$
$46÷5=9······1$
$3×2=6$
$1×4=4$
$81÷9=9$
$5×6=30$
$6÷3=2$
$5×1=5$
$42÷7=6$
$270+400=670$
$52+29=81$
$900-300=600$
$300+500=800$
$510-70=440$
$760+30=790$
$42+36=78$
$700-200=500$
$7000-3000=4000$
$70+320=390$
$740-60=680$
$400+600=1000$
$100-60=40$
$300+700=1000$
$32+65=97$
$700-300=400$
$640-60=580$
$930-300=630$
$3000+600=3600$
$65÷7=9······2$
$75÷9=8······3$
$81÷9=9$
$65÷8=8······1$
$32÷7=4······4$

拓展园地
乐乐和5个同学一起参加跳绳比赛，每两个同学之间都要比赛一场，这次比赛一共要进行多少场？

15场