Question

3.2×2.8+13.64用简便计算？

Answer 1

3.2×2.8+13.64用简便计算

解：根据已知条件，列式计算

3.2×2.8+13.64

=3.2x（3-0.2）+13.64

=3.2x3-3.2x0.2+13.64

=9.6-0.64+13.64

=9.6+（13.64-0.64）

=9.6+13

=22.6

Answer 2

根据公式（.a+ b）（a-b）= a²-b²，可以把
3.2×2.8转换成（3+0.2）（3-0.2）=3²-0.2²
具体过程如下:
3.2×2.8+13.64
=（3+0.2）×（3-0.2）+13.64
=3²-0.2²+13.64
=，9-0.04+13.64
=9+13.64-0.04
=9+（13.64-0.04）
=9+13.6
=22.6

Answer 3

本题简便计算的要诀在将3.2或2.8进行变化，然后利用乘法分配律逆运用计算。具体如下:
3.2×2.8+13.64
=(3+0.2)×2.8+13.64
=3×2.8+0.2×2.8+13.64
=8.4+0.56+13.64
=8.96+13.64
=22.6

Answer 4

3.2×2.8+13.64

＝3.2×（3-0.2）+13.64

＝3.2×3-3.2×0.2+13.64

＝9.4-0.64+13.64

=22.4

Answer 5

3.2×2.8+13.64用简便计算？

3.2×2.8+13.64
=8.96+13.64
=13.64+9-0.04
=22.64-0.04
=22.6