问题描述:
(2980+5/6+7/8+7/10)÷(5/6+7/8+7/10)
1 1 1 1
_______+ _____ + _____+.+_____
1X2X3 2X3X4 3X4X5 20X21X22
1 1 1 1
_______+ _____ + _____+.+_____
1X2X3 2X3X4 3X4X5 20X21X22
问题解答:
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