New
New

Solve one and two-step problems in different contexts

I can solve one and two-step problems in different contexts.

New
New

Solve one and two-step problems in different contexts

I can solve one and two-step problems in different contexts.

Lesson details

Key learning points

  1. When a part is missing, subtract the other part from the whole.
  2. When the whole is missing, add the parts together.
  3. Look for the strategy which is most efficient.

Common misconception

Pupils may try to solve problems without thinking about the numbers involved.

Encourage pupils to look at the calculations and think about the numbers involved. Pupils may not get the most efficient method first time so encourage them to think about their responses and learn from what other children have done.

Keywords

  • Efficient - Working efficiently means finding a way to solve a problem quickly whilst also maintaining accuracy.

In this session, pupils look for missing numbers in calculations, trying to find the most efficient way of finding the answer. Some pupils may benefit from the use of base ten blocks or bar models, although pupils should be familiar with using additive relationships to reorder calculations.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
What is the missing number? 2 + $$\square$$ = 30
Correct Answer: 28, twenty-eight
Q2.
What is the missing number? $$\square$$ − 5 = 8
Correct Answer: 13, thirteen
Q3.
What is 25 + 7 − 5 =
Correct Answer: 27, twenty-seven
Q4.
What is 178 + 40 − 30 =
Correct Answer: 188
Q5.
What is 135 + 99 =
Correct Answer: 234, two hundred and thirty-four
Q6.
What is 201 − 24 + 25 =
Correct Answer: 202, two hundred and two

6 Questions

Q1.
What is the most efficient way of finding the missing number? $$\square$$ + 298 = 301
Add 301 and 298 together
Subtract 298 from 301
Correct answer: Add on from 298 to 301
Q2.
Find the missing number. $$\square$$ − 7 = 37
30
34
43
Correct answer: 44
Q3.
Find the missing number. 41 − = 11
Correct Answer: 30, thirty
Q4.
Find the missing number. 402 + 50 − = 412
Correct Answer: 40
Q5.
41 snails are on a log. Some snails creep away. There are now 27 snails on the log. How many snails crept away?
Correct Answer: 14, fourteen
Q6.
285 people are on a train. At the next stop, 59 people get off and 60 get on. How many people are on the train now?
Correct Answer: 286, two hundred and eighty-six

Lesson appears in

UnitMaths / Understand additive relationships and apply them to rearrange equations