The quotient has the digit 0

### 1.1. Knowledge to remember

a) **9450 : 35 = ?**

*Sort in order from left to right:*

- 94 divided by 35 gives 2, write 2 ;

2 times 5 equals 10; 14 minus 10 equals 4, write 4 remember 1 ;

2 times 3 equals 6, adding 1 equals 7 ; 9 minus 7 equals 2, write 2.

- Down 5, get 245 ; 245 divided by 35 gives 7, write 7 ;

7 times 5 equals 35 ; 35 minus 35 equals 0, write 0 remember 3 ;

7 times 3 equals 21, add 3 equals 24 ; 24 minus 24 equals 0, write 0.

- Lower 0 ; 0 divided by 35 gets 0, write 0.

\(\begin{array}{l}

\begin{array}{*{20}{c}}

{9450}\\

{245\,\,\,}

\end{array}\left| {\begin{array}{*{20}{c}}

{35}\\

\hline

{270}

\end{array}} \right.\\

\,\,\,000

\end{array}\)

9450 : 35 = 270.

b) **2448 : 24 = ?**

*Sort in order from left to right:*

- 24 divided by 24 is 1, write 1 ;

1 times 4 equals 4; 4 minus 4 equals 0, write 0 ;

1 times 2 equals 2; 2 minus 2 equals 0, write 0.

- Lower 4 ; 4 divided by 24 gives 0, write 0.
- Lose 8, get 48 ; 48 divided by 24 gives 2, write 2 ;

2 times 4 equals 8; 8 minus 8 equals 0, write 0.

2 times 2 equals 4; 4 minus 4 equals 0, write 0.

\(\begin{array}{l}

\begin{array}{*{20}{c}}

{2448}\\

{0048\,}

\end{array}\left| {\begin{array}{*{20}{c}}

{24}\\

\hline

{102}

\end{array}} \right.\\

\,\,\,\,\,\,00

\end{array}\)

2448 : 24 = 102.

### 1.2. Solving Textbook Exercises

**Lesson 1:** Calculate then calculate

a) 8750 : 35 b) 2996 : 28

23520 : 56 2420 : 12

11780 : 42 13870 : 45

**Solution guide:**

- Set calculated by vertical column and divided in order from left to right.

**Lesson 2**: A water pump in 1 hour 12 minutes pumps 97,200 liters of water into the swimming pool. How many liters of water per minute on average?

- Change: 1 hour 12 minutes = 72 minutes.
- Calculate the average number of liters of water per minute that the machine can pump, we take the total number of liters of water pumped into the tank divided by 72.

*Solution*

Exchange: 1 hour 12 minutes = 72 minutes

On average, the number of liters of water pumped per minute is:

97200 : 72 = 1350 (liters)

Answer: 1350 liters of water.

**Lesson 3: **A rectangular piece of land has the sum of the lengths of two consecutive sides equal to 307m, the length is 97m more than the width.

a) Calculate the perimeter of that piece of land;

b) Calculate the area of that land.

__Solution guide:__

- The sum of the lengths of two consecutive sides is half the perimeter of the land.
- Perimeter = half circumference x 2
- Calculate the length and width according to the problem of finding two numbers when the sum and difference are known:

Large number = (Sum + difference) : 2; Small number = (sum – difference): 2

- Area = length x width.

*Solution*

a) The perimeter of the land is:

307 x 2 = 614 (m)

b) The width of the land is :

(307 – 97) : 2 = 105 (m)

Land length:

105 + 97 = 202 (m)

The land area is:

202 x 105 = 21210 (m2)

Answer: a) Perimeter: 614m;

b) Area: 21210m^{2}.

.

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