Solve addition calculations mentally by using known facts

I can solve addition calculations mentally by using known facts.

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Year 6

Solve addition calculations mentally by using known facts

I can solve addition calculations mentally by using known facts.

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Share activities with pupils

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Lesson details

Key learning points

If I increase this addend by __ then the sum will increase by the same amount.
If I decrease this addend by __ then the sum will decrease by the same amount.
A balance beam can represent unequal expressions or inequalities.

Keywords

Equation - An equation is used to show that one number, calculation or expression is equal to another.
Adjustment - An adjustment is a change to a number using either subtraction or addition.
Whole - The whole is all the parts or everything, the total amount.
Part - A part is a piece or section of the whole.

Common misconception

Pupils may find it hard to understand that recalculating the adjusted part is an unnecessary step.

Display two sets of workings side-by-side. In the 1st, show the adjusted part being recalculated. In the 2nd, show it without recalculating the part. Pupils will hopefully see that the solution emerges from both.

Number bonds to 100 and 1,000 are very useful here and always worth practising. They could be used as a basis for early morning work or you could verbally challenge the children as they're lining up for assembly. Remember, success breeds motivation!