Partition to 100 | Worksheets - Primary Stars Education - Free Printable

The image shows three worksheets titled "Partition numbers to 100", each with a series of part-whole models (also known as "part-part-whole" diagrams). These are used in mathematics education to help students understand how numbers can be broken down into parts.

In each diagram:
- The top circle represents the whole number.
- The two bottom circles represent parts that add up to the whole.
- The goal is to complete the missing part(s) so that the sum of the two parts equals the whole.

We’ll solve each one step by step using simple subtraction:
> Missing part = Whole − Known part

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✔ Worksheet 1 (Left)

#### a) 51
- One part = 50
- Missing part = 51 − 50 = 1

#### b) 22
- One part = 20
- Missing part = 22 − 20 = 2

#### c) 18
- One part = 8
- Missing part = 18 − 8 = 10

#### d) 49
- One part = 9
- Missing part = 49 − 9 = 40

#### e) 72
- One part = 70
- Missing part = 72 − 70 = 2

#### f) 45
- One part = 40
- Missing part = 45 − 40 = 5

#### g) 76
- One part = 6
- Missing part = 76 − 6 = 70

#### h) 32
- One part = 2
- Missing part = 32 − 2 = 30

#### i) 83
- One part = 83 (same as whole) → This seems like a trick!
- So the other part must be 0? But likely, it's meant to be split differently. Wait — the top is 83, and one part is 83, so the other must be 0.
- But maybe it’s a typo or misprint? Let's assume it's correct: 0

#### j) 91
- One part = 1
- Missing part = 91 − 1 = 90

#### k) 26
- One part = 20
- Missing part = 26 − 20 = 6

#### l) 57
- One part = 50
- Missing part = 57 − 50 = 7

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✔ Worksheet 2 (Middle)

#### a) 67
- One part = 60
- Missing part = 67 − 60 = 7

#### b) 43
- One part = 40
- Missing part = 43 − 40 = 3

#### c) 22
- One part = 2
- Missing part = 22 − 2 = 20

#### d) 34
- One part = 4
- Missing part = 34 − 4 = 30

#### e) 17
- One part = 10
- Missing part = 17 − 10 = 7

#### f) 87
- One part = 80
- Missing part = 87 − 80 = 7

#### g) 55
- No part given → need to partition arbitrarily?
- But both parts are blank → we can choose any two numbers that add to 55.
- Example: 50 + 5 (or 25 + 30, etc.) → but usually they want tens and units.
- Likely intended: 50 + 5

#### h) 92
- Both parts blank → again, possible answer: 90 + 2

#### i) 13
- Both parts blank → 10 + 3

#### j) 45
- Both parts blank → 40 + 5

#### k) 54
- Both parts blank → 50 + 4

#### l) 71
- Both parts blank → 70 + 1

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✔ Worksheet 3 (Right)

#### a) 73
- Both parts blank → 70 + 3

#### b) 96
- Both parts blank → 90 + 6

#### c) 61
- Both parts blank → 60 + 1

#### d) 32
- Both parts blank → 30 + 2

#### e) 18
- Both parts blank → 10 + 8

#### f) 57
- Both parts blank → 50 + 7

#### g) 49
- Both parts blank → 40 + 9

#### h) 51
- Both parts blank → 50 + 1

#### i) 66
- Both parts blank → 60 + 6

#### j) 81
- Both parts blank → 80 + 1

#### k) 29
- Both parts blank → 20 + 9

#### l) 15
- Both parts blank → 10 + 5

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📌 Summary of Answers

#### Worksheet 1:
| Letter | Top | Part A | Part B |
|--------|-----|--------|--------|
| a | 51 | 50 | 1 |
| b | 22 | 20 | 2 |
| c | 18 | 10 | 8 |
| d | 49 | 40 | 9 |
| e | 72 | 70 | 2 |
| f | 45 | 40 | 5 |
| g | 76 | 70 | 6 |
| h | 32 | 30 | 2 |
| i | 83 | 0 | 83 |
| j | 91 | 90 | 1 |
| k | 26 | 20 | 6 |
| l | 57 | 50 | 7 |

#### Worksheet 2:
| Letter | Top | Part A | Part B |
|--------|-----|--------|--------|
| a | 67 | 60 | 7 |
| b | 43 | 40 | 3 |
| c | 22 | 20 | 2 |
| d | 34 | 30 | 4 |
| e | 17 | 10 | 7 |
| f | 87 | 80 | 7 |
| g | 55 | 50 | 5 |
| h | 92 | 90 | 2 |
| i | 13 | 10 | 3 |
| j | 45 | 40 | 5 |
| k | 54 | 50 | 4 |
| l | 71 | 70 | 1 |

#### Worksheet 3:
| Letter | Top | Part A | Part B |
|--------|-----|--------|--------|
| a | 73 | 70 | 3 |
| b | 96 | 90 | 6 |
| c | 61 | 60 | 1 |
| d | 32 | 30 | 2 |
| e | 18 | 10 | 8 |
| f | 57 | 50 | 7 |
| g | 49 | 40 | 9 |
| h | 51 | 50 | 1 |
| i | 66 | 60 | 6 |
| j | 81 | 80 | 1 |
| k | 29 | 20 | 9 |
| l | 15 | 10 | 5 |

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🔍 Explanation

These exercises teach place value and number bonds. Students learn that:
- Numbers can be split into tens and ones (e.g., 57 = 50 + 7).
- The total (whole) is always the sum of its parts.
- This builds mental math skills and understanding of addition/subtraction.

💡 Tip for students: Use base-10 blocks or counters if needed. For example, 45 can be shown as 4 tens and 5 ones.

Let me know if you'd like this formatted as a printable answer sheet!