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在学习用乘法口诀求商时,同学们常常会遇到这样的问题:在()里最大能填几?()×7<25 33>6×()46>8×()6×()<43该怎样来解答这样的问题呢?其实我们可以联系乘法口诀来想。比如:()×7<25,我们就想7的乘法口诀,一七得七,二七十四,三七二十一,四七二十八,28已经超过了25,所以最大只能填3,即(3)×7<25。同样的道理,33>6×(),想:五六三十,六六三十六,括号里填5;
When studying multiplication formulas, students often encounter such questions as: Can the maximum number of fields be filled in ()? () × 7 <25 33> 6 × () 46> 8 × () 6 × () <43 How to solve such a problem? In fact, we can contact the multiplication formula to think. For example: () × 7 <25, we would like seven multiplication formulas, seven seven, two seventy-four, three seven twenty-one, four seven twenty-eight, 28 has more than 25, so the maximum can only be filled 3, ie (3) × 7 <25. The same token, 33> 6 × (), think: fifty-six thirty, six thirty-six, fill in brackets 5;