Question

3.9×9.9+0.38的简便运算？

Answer 1

先把算式3.9×9.9+0.38写成3.9×（10-0.1）+0.38
然后算式=3.9×10-3.9×0.1+0.38=39-0.39+0.38
最后算式=39-0.01=38.99

Answer 2

=3.9*9.9+0.39-0.01

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=3.9*(9.9+0.1)-0.01

=39-0.01

=38.99

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如上所述过程

Answer 3

你好此题简便运算方法为3.9×9.9+0.38=3.9×（10一0.1）+0.38=3.9×10一3.9×0.1+0.38=39一（0.39一0.38）=39一0.01=38.99

Answer 4

解：3.9×9.9+0.38等于（ 3899/100 ），【即等于38.99】
∵已知需求出3.9×9.9+0.38等于多少
∴3.9 × 9.9 + 0.38
= （3×10+9）/10 × （9×10+9）/10 + 38/100

= 39/10 × 99/10 + 38/100
= 3861/100 + 38/100
= 3899/100
= 38.99
答：3.9×9.9+0.38等于3899/100，【即等于38.99】

Answer 5

3.9×9.9+O.38
=3.9×9.9+0.39-0.01
=3.9×9.9+3.9×0.1-0.01
=3.9×(9.9+0.1)-0.01
=3.9×10-0.01
=39-0.01
=38.99