New
New
Year 2

Solve problems involving addition and subtraction

I can solve problems involving the addition and subtraction of two-digit numbers.

New
New
Year 2

Solve problems involving addition and subtraction

I can solve problems involving the addition and subtraction of two-digit numbers.

Lesson details

Key learning points

  1. When solving problems, it must be decided whether to add or subtract in order to solve it.
  2. If the ones digits crosses the tens boundary, it shows that the bridge 10 strategy can be used.
  3. A number line can be drawn or visualised to help solve problems efficiently.

Common misconception

When solving problems involving equations with more than two parts, children may automatically consider the numbers in the order given instead of considering the order they would find easier.

Encourage children to solve equations in different orders, comparing which they find easiest and articulating their thinking as they calculate.

Keywords

  • Addition - Addition involves finding the total, or sum, by combining two or more numbers.

  • Subtraction - Subtraction involves taking one number away from another.

  • Bridge 10 - An addition or subtraction strategy where numbers are partitioned to reach the previous or next multiple of 10, so bonds to 10 can be used to calculate more efficiently.

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.
Write a subtraction equation that could be represented by this bar model and solve it.
An image in a quiz
Correct Answer: 25 − 24 = 1
Q2.
Which of the following equations will have a difference of 1?
64 − 54 = ?
82 − 28 = ?
Correct answer: 88 − 87 = ?
Q3.
One of the missing numbers in this equation is 93 Which of the following could be the other missing number? ___ − ___ = 1
Correct answer: 92
Correct answer: 94
83
Q4.
In which of the following equations will the missing part be a multiple of 10?
37 − 36 = ?
22 − 20 = ?
Correct answer: 61 − 31 = ?
Q5.
Solve the equation. 71 − 41 =
Correct Answer: 30
Q6.
What is the missing digit in the equation?
An image in a quiz
Correct Answer: 9

6 Questions

Q1.
89 points are needed to buy these trainers and the t-shirt. How many points do the trainers cost? Which equation would solve this problem?
An image in a quiz
Correct answer: 89 − 47 = ?
89 + 47 = ?
Q2.
What is the total cost of the hat and the glasses?
An image in a quiz
51 points
Correct answer: 61 points
56 points
Q3.
Match the equations that will have the same total.
Correct Answer:34 + 20 + 19 = ?,20 + 19 + 34 = ?

20 + 19 + 34 = ?

Correct Answer:23 + 30 + 13 = ?,30 + 13 + 23 = ?

30 + 13 + 23 = ?

Correct Answer:42 + 20 + 15 = ?,20 + 15 + 42 = ?

20 + 15 + 42 = ?

Q4.
Which number line represents the same equation as the number line shown?
An image in a quiz
A
B
Correct answer: C
Q5.
First, Andeep had 86 points. Then, he bought a hat. Then, he bought a pair of glasses. How many points did he have left? 86 − 30 − 32 = ? Andeep had points left.
An image in a quiz
Correct Answer: 24
Q6.
Choose an equation to represent the problem. Then, solve it. First, Izzy had 78 points. Then, she bought a t-shirt. Then, she bought a pair of shoes. How many points does she have left?
An image in a quiz
Correct answer: 78 − 35 − 20 = 21
Correct answer: 78 − 20 − 35 = 21
35 + 20 = 55
78 − 35 = 43