Module 3 Calculating
Select each tab to find out more or use the breadcrumb trail to go to another part of this resource.
Can I add and subtract two numbers in my head quickly?

Example review questions

  • 5-second mental questions
    • What must be added to 74 to make 100?
    • What is 60 more than 23?
    • Add 45 and 51.
    • Subtract 12 from 90. Explain your method.
    • What is 100 subtract 21? How did you work this out?
  • 10-second mental questions
    • If Max has 19p and Dan has 29p, how much do they have altogether?
    • How many less than 62 is 28?
    • There are 66 children in Year 6. If 37 are girls, how many are boys?
  • 15-second mental questions
    • Add together 18, 24 and 82. Explain your method.

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 Can I add and subtract two numbers in my head quickly? - teaching guidance | 40KB new window

Consolidation and practice

These resources are to support children in guided or independent work.

SWF file Swimming race | 120KB new window

SWF file Number strength | 882KB new window

SWF file Long jump | 89KB new window

SWF file Empty box | 875KB new window

PDF file Springboard 5, Unit 3 (Additional materials) Addition and subtraction facts | 86KB new window

PDF file Springboard 7, Unit 1, Sections 3 and 4 Mental addition, Mental subtraction | 1MB new window

Calculating angles

itp_calculating_angles.png

This interactive teaching program (ITP) is an ICT-based tool to support the exploration of angles. Calculating angles ITP allows the child or teacher to represent single or multiple shapes rotated around a central point in one, two or four quadrants. The size of angles can be estimated or calculated and confirmed using the on-screen protractor or reveal function.

Polygon

itp_polygons.png

This interactive teaching program (ITP) is an ICT-based tool to support the exploration of shape, space and measure. Polygon ITP allows the child or teacher to represent regular polygons with three to ten sides. The ITP can then be used to explore the properties of regular and irregular shapes by dragging vertices and creating additional vertices. The ITP includes an on-screen protractor and ruler.

Fixing points

itp_fixing_points.png

This interactive teaching program (ITP) is an ICT-based tool to support the exploration of shape and space. Fixing points ITP allows the child or teacher to create one or more shapes by connecting a number of vertices on a grid. Angles can be estimated and measured, and the effect of moving different vertices can be explored.

Opportunities to use and apply

Possible contexts include:

  • money, e.g. Total a shopping bill such as 45p + 32p + 55p + 12p.
  • measures, e.g. I have 360 ml of juice in a jug. I add another 450 ml. How much juice is there in the jug now?
  • application to calculations where known facts and place value can be used to add and subtract a pair of numbers mentally, e.g. Using knowledge of 62 − 38 to calculate
    6200 − 3800 or 6.2 − 3.8.
  • solving problems, e.g. Completing number pyramids.
    A number pyramid. Top row: 32. Next row: blank, 15. Next row: blank, eight, blank. Bottom row: four, blank, three, blank.

Confirming learning

Ask probing questions such as:

  • The difference between two two-digit numbers is 13. What could the two-digit numbers be? If one of the numbers is between 50 and 60 what could the numbers be?
  • How could you quickly calculate the answer to 93 − 86? Why did you choose that strategy?
  • Use numbers greater than 20 to make up an addition that has the answer 87.
  • The total of two numbers is 33 and their difference is 7. What are the numbers? What would they be if the total was 3.3 and the difference 0.7? How do you know?