问题 解答题
用简便方法计算.
7.26-2.38+12.74-7.62
67÷
4
5
÷12.5
7
13
×
9
17
+
9
17
×
6
13
87×
87
88
51×3.2+32×4.9.
答案

(1)7.26-2.38+12.74-7.62,

=(7.26+12.74)-(2.38+7.62),

=20-10,

=10;

(2)67÷

4
5
÷12.5,

=67÷(

4
5
×12.5),

=67÷10,

=6.7;

(3)

7
13
×
9
17
+
9
17
×
6
13

=(

7
13
+
6
13
)×
9
17

=1×

9
17

=

9
17

(4)87×

87
88

=(88-1)×

87
88

=88×

87
88
-
87
88

=87-

87
88

=86

1
88

(5)51×3.2+32×4.9,

=51×3.2+3.2×49,

=(51+49)×3.2,

=100×3.2,

=320.

单项选择题
单项选择题