1. 直接写出得数。
$1 - 0.19 =$
$0.1 - 0.01 =$
$10.05 + 5.8 =$
$0.46 + 0.3 =$
$2.11 + 3.22 =$
$12.5 + 12.5 =$
$2 - 1.5 =$
$0.27 + 0.43 =$
$5.32 - 2.3 =$
$10 - 7.36 =$
$5.5 + 4.5 =$
$4.39 - 4.3 =$
$17×40 =$
$100 - 63 =$
$3.2 + 1.68 =$
$14 - 7.4 =$
$1.92×1 =$
$0.32×500 =$
$0.35×4 =$
$8.3 + 6.7 =$
$0.4×0.9 =$

$1 - 0.19 = 0.81$
$0.1 - 0.01 = 0.09$
$10.05 + 5.8 = 15.85$
$0.46 + 0.3 = 0.76$
$2.11 + 3.22 = 5.33$
$12.5 + 12.5 = 25$
$2 - 1.5 = 0.5$
$0.27 + 0.43 = 0.7$
$5.32 - 2.3 = 3.02$
$10 - 7.36 = 2.64$
$5.5 + 4.5 = 10$
$4.39 - 4.3 = 0.09$
$17×40 = 680$
$100 - 63 = 37$
$3.2 + 1.68 = 4.88$
$14 - 7.4 = 6.6$
$1.92×1 = 1.92$
$0.32×500 = 160$
$0.35×4 = 1.4$
$8.3 + 6.7 = 15$
$0.4×0.9 = 0.36$

2. 列竖式计算。
$10.8 + 30.5 =$
$5 - 2.627 =$
$15.2 - 4.38 =$

10.8
+ 30.5
------
41.3
5.000
2.627
------
2.373
15.20
4.38
------
10.82

3. 解决问题。
下面是妈妈有一次去超市购物的购物清单。估一估妈妈一共花了多少元钱？

15.6≈16
25.6≈26
19.2≈19
3.3≈3
3.8≈4
16+26+19+3+4=68（元）
答：妈妈一共大约花了68元钱。