Question

13.9×61+3.9×1.39的简便方法？

Answer 1

13.9×0.61＋3.9×1.39
＝13.9×0.61＋0.39×13.9
＝13.9×(0.61＋0.39)
＝13.9×1
＝13.9
(疑似题目有误，已更正)

Answer 2

13.9 x61+3.9 x 1.39
=13.9 x 61 +13.9 x 0.39
=13.9 x (61+0.39)
=13.9 x 61.39
=853.321