Answers to page 62 to 67 below - answers to page 68 next page

Answers to page 68

1. Multiplying and dividing decimals by 10, 100 and 1000a. 5.3b. 242.47c. 12.3d. 690e. 500.2f. 2870g. 2.71h. 0.075i. 8.7j. 0.0123k. 4.87l. 0.0261

2. Multiplying and dividing decimals by single digitsa. 16.38b. 21.18c. 1.69d. 2.85

3. This is a two-step problem. First you must add the cost of the items to get the total spend, then you must take that away from the £5 note.

a. £1.75 + £0.53 = £2.28b. £5.00 - £2.28 = £2.72

4. Problem-solving mixed operations.a. To calculate how many tins you need, you must divide the area you are painting

(76.5) by the amount you know one tin covers (9), 76.5 divided by 9 = 8.5. You won’t be able to buy half a tin, so you need 9 tins to complete the job.

b. It’s £6.50 per tin and you have worked out you need 9 tins so you must multiply 6.5 by 9 to get your total cost = £58.50. Because you are answering in pounds you cannot say £58.5, rather we add the zero to mean 58 pounds and 50 pence.

5. This problem requires division. 4 tyres cost £174.40 so one tyre is a quarter of that cost. 174.4 divided by 4 = £43.60. As above you need to add the zero on when you are writing in pounds.

6. 55 x 1.485 = 81.675 and you have been asked to round to 1dp. 81.675 sits between 81.6 and 81.7. The answer rounded to 1dp is 81.7.

7. 12.5 litres takes him 157.5 miles. So, to calculate how far he can travel on 1 litre you must divide the total distance by 12.5 which equals 12.6. Answer using the correct units, ie. 12.6 miles per litre.

8. 30 disks for £2.16 means each disk costs £0.072 (7.2p), 200 disks for £14.60 means each disk costs £0.073 (7.3p). This means the Print Out Computers are more expensive by 0.1p per disk.