New
New
Year 2
Find the missing addend when adding two-digit numbers
I can find the missing addends when adding two-digit numbers.
New
New
Year 2
Find the missing addend when adding two-digit numbers
I can find the missing addends when adding two-digit numbers.
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Lesson details
Key learning points
- Two-digit numbers can be partitioned to help find a missing digit or a missing addend.
- One equation can be used to help solve another equation.
- The patterns in equations can be used to help find a missing addend.
Keywords
Addend - Any of the numbers that are added together.
Digit - A single symbol used to make a numeral.
Common misconception
When finding a missing ones digit in an addend, children may confuse the tens and ones digits in the sum, thus adding to the ones to make the amount of the tens digit or vice versa.
Partition the addends into tens and ones so the place value of the digit that is missing is clear.
Begin working practically with Base 10 blocks to help visualise the equation. Check the movement of the blocks when exploring equivalent expressions. Encourage children to mentally manipulate numbers by predicting equivalent calculations before checking.
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).
Lesson video
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Starter quiz
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6 Questions
Q1.
Match the expressions which will have the same sum.
53 + 42
63 + 21
71 + 22
Q2.
Which expression will have the same sum as 14 + 53?
41 + 35
31 + 45
Q3.
Which equation will have a sum in the fifties?
32 + 45 = ?
17 + 22 = ?
Q4.
Which equation will have a greater sum than 25 + 61 = ?
52 + 22 = ?
25 + 41 = ?
Q5.
40 + + 5 + 3 = 43 + 25
Q6.
67 + 21 = 88, so 61 + 27 =
Exit quiz
Download exit quiz
6 Questions
Q1.
Which digit is missing in this equation?
Q2.
Which of the following is the missing addend?
51
37
Q3.
Use the first equation to help solve the second equation.
Q4.
Which of the following cannot be one of the tens digits in the equation?
3
2
Q5.
One of the Base 10 blocks has been moved over from one addend to the other. Which of the following could show the new equation? Tick two.
54 + 32 = 64 + 42
Q6.
Find the missing addend.
