Year 5

We can use a calculator to solve a problem and know how to interpret numbers as they appear on the calculator.

Year 5 Unit 14

What we are learning:

• To develop confidence in using a calculator your child needs lots of opportunities to use a calculator. Most mobile phones have a calculator so there is normally one at hand
• Make sure that your child has experience of inputting decimal numbers and amounts of money into a calculator and ask them what they notice when they input £56.70 – discuss why the calculator records this as 56.7.
• Remember that you cannot use a calculator to solve time problems in minutes and hours, e.g. 1 hour 25 minutes + 2 hours and 55 minutes is NOT the same as 1.25 +2.55 as there are 60 minutes in an hour, not 100. In the same way, to find the difference between 11.35am and 1.45pm you CANNOT do 1.45 – 11.35.

ACTIVITY 1: USING A CALCULATOR TO SOLVE PROBLEMS

Activities you can do at home:

Add or subtract money on a calculator – for example:
£84.58 – £38. 28 ~ the calculator will display the answer as 46.3 and the child needs to interpret this in terms of the context of the original question – in this case money.£67.23 + £28.57 ~ the calculator will display the answer as 95.8 ~ How will you record this answer? (it should be £95.80)

Multiply metric measurements on a calculator – for example 3m 28cm x 18 – we need to know that to enter 3m and 28cm we enter 3.28 (m) into the calculator and that the answer is in meters.

Have a go at the Calculator Questions sheet together.

Good questions to ask:

Why can’t we use the calculator to work out calculations in hours and minutes?
How do we enter four metres and twenty eight centimetres into the calculator?
How do we enter thirty three pounds and three pence?
If you see 4.04 in the calculator and you know it is money, how much have you got?

If your child:

Misinterprets the calculator display, e.g. thinks that £5.7 on the calculator is five pounds and seven pence as opposed to five pounds and seventy pence
Discuss place value together and explore the fact that the column to the right of the decimal point is tenths – in this case a tenth of a pound or ten pence. Therefore the 7 in that column stands for 7 groups of 10 pence or seventy pence.

Is confident and competent with a calculator
Encourage your child to estimate answers mentally or with jottings before using the calculator to work out the precise answer.