39x109-39的简便计算是

39x109-39的简便计算是
2025-03-24 21:52:32
推荐回答(3个)
回答1:

39x109-39
=39x(109-1)
=39x108
=(40-1)x108
=40x108-1x108
=4320-108
=4212

回答2:


如图

回答3:

39x109-39
=39x100+39×9-39
=3900+39×10-39-39
=4290-78
=4212