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$3.2 + 0.7 - 0.7=$
$11.2 + 4.3 - 0.2=$
$5.7 - 0.7 - 3.2=$
$3.2 + 0.7 - 0.7=$
3.2
$15.3 - 2.2 - 7.8=$5.3
$7.19 + 0.81 + 32.4=$40.4
$11.2 + 4.3 - 0.2=$
15.3
$8.3 - 8.2 + 8.2=$8.3
$4.7 + (9.1 - 4.7)=$9.1
$5.7 - 0.7 - 3.2=$
1.8
$4.5 - 2.7 - 0.3=$1.5
$2.69 - (0.69 + 0.04)=$1.96
答案
1. $3.2 + 0.7 - 0.7$
$=3.2+(0.7 - 0.7)$
$=3.2+0$
$= 3.2$
2. $15.3 - 2.2 - 7.8$
$=15.3-(2.2 + 7.8)$
$=15.3 - 10$
$= 5.3$
3. $7.19 + 0.81 + 32.4$
$=(7.19 + 0.81)+32.4$
$=8+32.4$
$= 40.4$
4. $11.2 + 4.3 - 0.2$
$=(11.2 - 0.2)+4.3$
$=11+4.3$
$= 15.3$
5. $8.3 - 8.2 + 8.2$
$=(8.2 - 8.2)+8.3$
$=0 + 8.3$
$= 8.3$
6. $4.7 + (9.1 - 4.7)$
$=(4.7 - 4.7)+9.1$
$=0+9.1$
$= 9.1$
7. $5.7 - 0.7 - 3.2$
$=(5.7 - 0.7)-3.2$
$=5 - 3.2$
$= 1.8$
8. $4.5 - 2.7 - 0.3$
$=4.5-(2.7 + 0.3)$
$=4.5 - 3$
$= 1.5$
9. $2.69 - (0.69 + 0.04)$
$=(2.69 - 0.69)-0.04$
$=2 - 0.04$
$= 1.96$
$=3.2+(0.7 - 0.7)$
$=3.2+0$
$= 3.2$
2. $15.3 - 2.2 - 7.8$
$=15.3-(2.2 + 7.8)$
$=15.3 - 10$
$= 5.3$
3. $7.19 + 0.81 + 32.4$
$=(7.19 + 0.81)+32.4$
$=8+32.4$
$= 40.4$
4. $11.2 + 4.3 - 0.2$
$=(11.2 - 0.2)+4.3$
$=11+4.3$
$= 15.3$
5. $8.3 - 8.2 + 8.2$
$=(8.2 - 8.2)+8.3$
$=0 + 8.3$
$= 8.3$
6. $4.7 + (9.1 - 4.7)$
$=(4.7 - 4.7)+9.1$
$=0+9.1$
$= 9.1$
7. $5.7 - 0.7 - 3.2$
$=(5.7 - 0.7)-3.2$
$=5 - 3.2$
$= 1.8$
8. $4.5 - 2.7 - 0.3$
$=4.5-(2.7 + 0.3)$
$=4.5 - 3$
$= 1.5$
9. $2.69 - (0.69 + 0.04)$
$=(2.69 - 0.69)-0.04$
$=2 - 0.04$
$= 1.96$
乘风破浪
$4 ÷ 10 =$
$3.14 × 100 =$
$18.6 ÷ 10 =$
$5.3 × 100 =$
$500 ÷ 1000 =$
解方程。
$x - 11.7 = 3.3$ $y - 1.7 = 2.6$ $18 + x = 44$
$4 ÷ 10 =$
0.4
$4 ÷ 100 =$0.04
$0.4 ÷ 10 =$0.04
$3.14 × 100 =$
314
$0.38 × 10 =$3.8
$0.007 × 100 =$0.7
$18.6 ÷ 10 =$
1.86
$27.4 ÷ 100 =$0.274
$216 ÷ 10 =$21.6
$5.3 × 100 =$
530
$9.32 × 1000 =$9320
$105 ÷ 1000 =$0.105
$500 ÷ 1000 =$
0.5
$0.7 ÷ 10 =$0.07
$44.35 × 100 =$4435
解方程。
$x - 11.7 = 3.3$ $y - 1.7 = 2.6$ $18 + x = 44$
答案
$4 ÷ 10 = 0.4$
$4 ÷ 100 = 0.04$
$0.4 ÷ 10 = 0.04$
$3.14 × 100 = 314$
$0.38 × 10 = 3.8$
$0.007 × 100 = 0.7$
$18.6 ÷ 10 = 1.86$
$27.4 ÷ 100 = 0.274$
$216 ÷ 10 = 21.6$
$5.3 × 100 = 530$
$9.32 × 1000 = 9320$
$105 ÷ 1000 = 0.105$
$500 ÷ 1000 = 0.5$
$0.7 ÷ 10 = 0.07$
$44.35 × 100 = 4435$
解方程：
$x - 11.7 = 3.3$
解：$x = 3.3 + 11.7$
$x = 15$
$y - 1.7 = 2.6$
解：$y = 2.6 + 1.7$
$y = 4.3$
$18 + x = 44$
解：$x = 44 - 18$
$x = 26$
$4 ÷ 100 = 0.04$
$0.4 ÷ 10 = 0.04$
$3.14 × 100 = 314$
$0.38 × 10 = 3.8$
$0.007 × 100 = 0.7$
$18.6 ÷ 10 = 1.86$
$27.4 ÷ 100 = 0.274$
$216 ÷ 10 = 21.6$
$5.3 × 100 = 530$
$9.32 × 1000 = 9320$
$105 ÷ 1000 = 0.105$
$500 ÷ 1000 = 0.5$
$0.7 ÷ 10 = 0.07$
$44.35 × 100 = 4435$
解方程：
$x - 11.7 = 3.3$
解：$x = 3.3 + 11.7$
$x = 15$
$y - 1.7 = 2.6$
解：$y = 2.6 + 1.7$
$y = 4.3$
$18 + x = 44$
解：$x = 44 - 18$
$x = 26$
圆满返航
在$□$里填上合适的数字。
$\begin{array}{r} □.4□\\ ×\ \ \ □.6\\ \hline □□8\\ □□5\ \ \\ \hline 8.□□□\end{array}$ $\begin{array}{r} 3\ 9.□\\ ×\ \ 0.3□\\ \hline □□8□\\ □□9\ 1\ \ \\ \hline 1□.□9\ 8\end{array}$
秘籍点拨 仔细观察竖式，找到可以先填的数字，再填其他数字，做到由简到难，循序渐进地解题。
第81片
$\begin{array}{r} $______$.4$______$\\ ×\ \ \ $______$.6\\ \hline $______$$______$8\\ $______$$______$5\ \ \\ \hline 8.$______$$______$$______$\end{array}$ $\begin{array}{r} 3\ 9.$______$\\ ×\ \ 0.3$______$\\ \hline $______$$______$8$______$\\ $______$$______$9\ 1\ \ \\ \hline 1$______$.$______$9\ 8\end{array}$
在$□$里填上合适的数字。
$\begin{array}{r} □.4□\\ ×\ \ \ □.6\\ \hline □□8\\ □□5\ \ \\ \hline 8.□□□\end{array}$ $\begin{array}{r} 3\ 9.□\\ ×\ \ 0.3□\\ \hline □□8□\\ □□9\ 1\ \ \\ \hline 1□.□9\ 8\end{array}$
秘籍点拨 仔细观察竖式，找到可以先填的数字，再填其他数字，做到由简到难，循序渐进地解题。
第81片
$\begin{array}{r} $______$.4$______$\\ ×\ \ \ $______$.6\\ \hline $______$$______$8\\ $______$$______$5\ \ \\ \hline 8.$______$$______$$______$\end{array}$ $\begin{array}{r} 3\ 9.$______$\\ ×\ \ 0.3$______$\\ \hline $______$$______$8$______$\\ $______$$______$9\ 1\ \ \\ \hline 1$______$.$______$9\ 8\end{array}$
答案
第一题竖式填空：
```
1.43
× 5.6
------
858
715
------
8.008
```
答案：1,3,5,8,5,7,1,0,0,8
第二题竖式填空：
```
39.7
× 0.34
------
1588
1191
------
13.498
```
答案：7,4,1,5,8,1,1,3,4
```
1.43
× 5.6
------
858
715
------
8.008
```
答案：1,3,5,8,5,7,1,0,0,8
第二题竖式填空：
```
39.7
× 0.34
------
1588
1191
------
13.498
```
答案：7,4,1,5,8,1,1,3,4
