Functional Skills: Division

When to Divide

You need to know when a question requires you to divide. There are two things to look out for:

1. Questions involving the words “divide” or “division” or similar.
2. Questions involving the divide sign, \div.

Division can also sneak into questions, for example through fractions or through wordy questions that give you a total and ask for a part of the total. This will be seen many times in this course.

Bus Stop Method

This method of division is called the bus stop method, because it looks like the shape of a bus stop. You can divide numbers to find whole number answers, decimal answers, or answers that have a remainder.

Example: Work out 288 \div 9, without using a calculator.

Step 1: Firstly, put the division into the Bus Stop seen below.

Step 2: See how many times 9 goes into the first digit, 2, which is \textcolor{limegreen}{0} times, so the \textcolor{red}{2} is carried to the next digit to make 28. The 0 goes above the bus stop.

Step 3: Next, see how many times 9 goes into 28. We know 3 \times 9=27, so 9 goes into 28 \textcolor{limegreen}{3} times with a remainder \textcolor{red}{1}, which is carried in front of the next digit to make 18. The 3 goes on top.

Step 4: Then, see how many times 9 goes into 18, which is \textcolor{limegreen}{2} times. The 2 goes above the bus stop.

So, the answer is,

288 \div 9 = \textcolor{blue}{32}

Dividing on a Calculator

The Bus Stop Method is for dividing without a calculator. Dividing with a calculator is significantly simpler. All you do is type the digits of one number, then press the divide symbol \div, then type the digits of the other number, then press equals.

Example: Use a calculator to find 5040 divided by 336.

Press 5 then 0 then 4 then 0 then \div then 3 then 3 then 6 then =.

Your calculator should give an answer of 15.

Dividing by \boldsymbol{10}, \boldsymbol{100}, \boldsymbol{1000}...

Dividing by powers of 10 is very similar to multiplying, except instead of moving the decimal point to the right, you move it to the left. The amount of times you move the decimal point depends on the amount of zeros.

• To divide by \textcolor{purple}{\boldsymbol{10}}, you move the decimal point one place to the left.
• To divide by \textcolor{purple}{\boldsymbol{100}}, you move the decimal point two places to the left.
• To divide by \textcolor{purple}{\boldsymbol{1000}}, you move the decimal point three places to the left.

Remember: For whole numbers the decimal point doesn’t look like it’s there, but it is. For example 25 can be written as 25.0

Checking Your Answer

Dividing is the opposite of multiplying. This means that, now we know how to do both, we can do one to check the other.

Example: Find 1536\div3, then perform a suitable check of your answer.

Use a calculator for this to find that 1536\div3=512

We can check this by multiplying 512 and 3 to make sure we get back to 1536

Use a calculator for this to find that 512\times3=1536

Example: Find 82\times21, then perform a suitable check of your answer.

Use a calculator for this to find that 82\times21=1722

We can check this by dividing 1722 by 21 to make sure we get back to 82

Use a calculator for this to find that 1722\div21=82