Mathematics and English progression

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      • Mental Calculation
        • Steps

Step 2 Objective

Use known number facts and place value to add or subtract mentally, including any pair of two-digit whole numbers.

Examples of what pupils should know and be able to do

Know

• What must be added to 37 to get to 100?
• 90 + 18
  + 30 = 82

• FTM(P)Y456 p 44 - Acrobat pdf document (20Kb)
• FTM(P)Y456 p 46 - Acrobat pdf document (20Kb)

• Number strings example of pupil's work - Acrobat pdf document (186Kb)
• Estimation example of pupils' work - Acrobat pdf document (199Kb)
• Answer of 100 question - Rtf (rich text format) document (48Kb)

Probing questions

Provide a range of calculations that cover the mental strategies taught (see Teaching mental calculation strategies to level 5 page 7 for list).

What strategies would you use to work out the answers to these calculations? Could you use a different method?

How could you check that your answer is correct?

What if pupils find this a barrier?

Identify which mental strategies are causing difficulties and focus teaching on these.

Encourage pupils to explain their mental strategies for adding pairs of two-digit numbers. Hearing other strategies helps develop understanding and extend calculation skills.

Refer to Teaching mental calculation strategies to Level 5 - Acrobat pdf document (554Kb) pp. 15-30.