口算
730﹣250= 260+90= 300×13= 8400÷40= 770+140= 2400÷200=
11×500= 9900÷900= 62万﹣25万= 18万+75万= （25×7）×4= 24×5=
口算
730﹣250= 260+90= 300×13= 8400÷40= 770+140= 2400÷200=
11×500= 9900÷900= 62万﹣25万= 18万+75万= （25×7）×4= 24×5=
= 1﹣40%=
= 52= 1÷
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= 1﹣
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