# Estimating and rounding

You said it was only going to be a few dollars.

Example 1

Where would you estimate $59.41 The choice would be  59.41 Round to the 1^(st) decimal place 59.40 Round to the units of 1 column 59.00 Round to the tens units 60.00 You can see that rounding to the tens units i.e.$60.00 is not too far from \$59.41 and is clearly easier to remember.

Example 2

The attendance at a football match is 34,846 people, how would you estimate this in order to tell your friends the attendance?

The choice would be

 34,846 Round to the tens units 34,850 Round to the hundreds units 34,800 Round to the thousands 35,000 Round to the tens of thousands 30,000

You can see that the most representative estimate would be 35,000 and would only be 154 out from the original number.

Example 3

Bernice decides to go shopping and in her trolley, she has two shirts for £10.99, three skirts for £21.20 and a pair of shoes for £69.00 She has £180. Estimate the value of the clothes to decide if she has enough.

 Adding 2times£10.99 + 3times£21.20 + 1times£69.00

is tough

 But adding 2times£10 + 3times£20 + 1times£70

is a lot easier

 2times£10 =£20 3times£20 =£60 1times£70 =£70 £150

She has enough

NOTE:

The real answer is £154.58 but the estimate of £150 is enough to realise that £180 is sufficient to purchase all the clothes.