Module 3 Calculating
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Can I make and justify decisions about when and how to use a calculator effectively to solve problems?

Example review questions

For each of these problems, decide whether to use a mental, written or calculator method. Give reasons for your choice and solve each problem:

  • Find the missing digits 3empty box + 85 = 1empty box3
  • Coach fares from Oxford to London are £13.50 for adults and £6.85 for children. How much will the total fare be for 3 adults and 6 children?
  • Amir buys a 5 kg sack of peanuts for £9.99. He measures out 150 g bags of peanuts and sells these for 65p each. How much profit will he make?
  • Apples weigh about 150 g each. How many apples would you expect to get in a 3 kg bag?
  • 29.6 × empty box = 1110

 

Teaching guidance

This teaching guidance document suggests some of the key vocabulary, models, images and practical equipment that children should experience and be able to use. It also includes some teaching tips to provide a few starting points for ways of supporting children with this area of mathematics.

PDF file Teaching guidance: Can I make and justify decisions about when and how to use a calculator effectively to solve problems? | 53KB new window

Consolidation and practice

These resources are to support children in guided or independent work. Roll over the highlighted resource for a description.

EXE file Empty box program | 874KB new window

PDF file Calculator activities | 2MB new window

XLS file Flexible problems spreadsheet | 205KB new window

XLS file Money problems spreadsheet | 96KB new window

DOC file Calculator problems | 38KB new window

Visit the nrich website new window for further activities to support practice and application.

Empty box program

image alt text here

This ICT-based tool can be used by children to practise and consolidate multiplication, division, addition and subtraction, and to develop understanding of inverse operations and when not to use a calculator. Different activities, numbers of questions and operations can be selected to vary the level of challenge.

Opportunities to use and apply

Possible contexts include:

  • Word problems, e.g. A pencil weighs about 3 g. A school buys 135 packs of 12. Approximately how much will these weigh in kg?
  • Money problems, e.g. How many notebooks costing £1.65 is it possible to buy with £50?
  • Data handling, e.g. Finding the mean of a set of data.
  • Problem-solving questions involving trial and improvement, e.g. Find the number that, when multiplied by itself, gives 2116
  • Empty box calculations: empty box ÷ 35.2 = 16.5

PDF file 'Mathematical challenges' Year 5 and Year 6: | 1.2MB new window A bit fishy; Spendthrift

Confirming learning

Decide which of these problems you would solve using a calculator.
Explain why and solve those problems:

  • A runner runs the 100 m four times. His times are: 11.25 s, 11.69 s, 10.8 s and 12.13 s. Find his average time.
  • A film starts at 4:25 pm and ends at 6:05 pm. How long is it?
  • 0.09 × empty box = 0.72
  • Find a number n such that n × (n+1) = 1332
  • Elena has a £50 budget to spend on a garden. She buys 18 packets of seeds costing £1.49 each, a spade costing £7.99 and a hose costing £12.49. How much money does she have left?
  • I buy a sheet of stamps. On the sheet there are 18 rows each containing twelve 35p stamps. How much will this cost?