**Five (5) **is ten divided by two ( **10 / 2 ), **so to divide a number by** 10/2, we**

- multiply it by 2, then
- divide by 10.

Since dividing by **10 **only involves moving the decimal point one place to the left, we can easily divide by** 5 **by just using** doubling **or** multiplication by 2.**

To divide a number by 5 we can either

Method A:

- double the number first then
- move the decimal point one place to the left.

Method B

- move the decimal point first then
- double the number.

We recommend the method B.

Let us try **method A **first.

Example 9.1: **Find 164 ÷ 5**

- Double
**16**is**32**and double**4**is**8.**So**164 x 2 is 328.** - Move the decimal point one place to the left to make it
**32.8.**

Now let us use the **method B.**

Example 9.2: Find **832 ÷ 5**

- Shifting the decimal point of the multiplicand one place to the left will make it
**83.2**. This also fixed the decimal point for the answer. - Doubling it gives
**166.4**.

Example 9.3: Find **1348 ÷ 50**

- Since
**50**is half of**100**or**10**we move the decimal point in^{2},**1348**two places to the left making it**13.48**. - We then double it to make it
**26.96**.

Example 9.4: Find **24.5 ÷ 0.5**

**0.5**is half of**1**or**10**so we do not have to adjust the decimal point. Just double the number to produce^{0 }**49.0.**- The answer becomes obvious if we double both the dividend and the divisor:
**24.5 ÷ 0.5 = 49.0 ÷ 1 = 49**

** **Example 9.5: How many mint candies costing **50** centavos each can I buy with **P 24.50?**

** **The figures here are the same as in Example 9.4 and the solution here clarifies the technique we used earlier: We can buy **2** candies for one peso; so for **24.50** pesos we can buy **24.5 x 2** or **49** candies.

Example 9.6: Find **376 ÷ 0.05**

**0.05**is half of**0.1**or**10**so we have to move the decimal point one place to the^{-1}**right**, meaning we have to add a zero making it**3,760**.- Doubling it would result to
**7,520.**

Exercise 9: Compute the following:

- ) 370 ÷ 5 =
- ) 535 ÷ 5 =
- ) 2,367 ÷ 5 =
- ) 9,898 ÷ 5 =
- ) 4,656 ÷ 50 =
- ) 24,579 ÷ 50 =
- ) 5,836 ÷ 500 =
- ) 34,785 ÷ 500 =
- ) 4,524 ÷ 0.5 =
- ) 3,645 ÷ 0.05 =

Answers to all exercises are found in the answer key.

Discover the 25 Math Short Cuts ( 25 MSC )!