In this activity, we will be using our rounding skills to **estimate** the answers to calculations.

When dealing with large quantities, it's common to round or estimate the values. For instance, if you come across a football match attendance of 31,555, and someone asks you about the attendance, you might round it off to around 30,000. It's advisable to round to **one significant figure**.

When we shop at the supermarket, we often use rounding to estimate our total bill. To do this, we round the cost of each item to one significant figure.

**Example 1**

Round off the values in the calculation to 1 significant figure to work out an estimate to the calculation below.

7.91 + 8.3

First, let's round each value to 1 significant figure:

7.91 → 8

8.3 → 8

Now we have our rounded values, we can find an estimate for the calculation:

8 + 8 = 16

**Example 2**

Round off the values in the calculation to 1 significant figure to work out an estimate to the calculation below.

8.3 ÷ 2.1

First, let's round each value to 1 sig. fig.

8.3 → 8

2.1 → 2

Now we have our rounded values, we can find an estimate for the calculation:

8 ÷ 2 = 4

Great ... let's try the activity!