直接写出得数．21×400=270万+650万=125×16×50=316+599=25十97十15十3=8650﹣250=2800÷25= ÷ =105…6．
直接写得数 24÷=﹣= 10+2.52=（﹣0.5）×=×=（+）×12=×÷×= 0.32×200=
计算下面各题．====+=====
口算：========
看图填空．
（1）红色+绿色=+= （2）黄色+黑色=+= （3）红色﹣黄色=﹣= （4）你还能提出什么数学问题？能解答吗？
直接写出得数．========
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