Let’s solve this step by step.
The task is to fill in the blanks by skip counting by 3. That means we add 3 each time to get the next number.
We’ll go row by row.
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Row 1 (blue circles):
Given: 0, 3, 6, 9, __, 15
We know:
0 + 3 = 3
3 + 3 = 6
6 + 3 = 9
9 + 3 =
12 ← that’s the missing number
12 + 3 = 15 → checks out!
✔ So, first blank =
12
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Row 2 (green circles):
Given: 18, __, 24, __, 30, 33
Start from 18:
18 + 3 =
21 ← first blank
21 + 3 = 24 → correct
24 + 3 =
27 ← second blank
27 + 3 = 30 → correct
30 + 3 = 33 → correct
✔ Blanks =
21 and
27
---
Row 3 (red circles):
Given: __, 39, 42, 45, 48, __
Work backwards from 39:
39 - 3 =
36 ← first blank
Check forward: 36 → 39 → 42 → 45 → 48 → then 48 + 3 =
51 ← last blank
✔ Blanks =
36 and
51
---
Row 4 (orange circles):
Given: 54, 57, __, 63, 66, 69
57 + 3 =
60 ← middle blank
Check: 60 + 3 = 63 → correct
✔ Blank =
60
---
Row 5 (purple circles):
Given: __, __, 78, 81, __, 87
Work backwards from 78:
78 - 3 =
75
75 - 3 =
72
So first two blanks: 72, 75
Then 81 + 3 =
84 → third blank
Check: 84 + 3 = 87 → correct
✔ Blanks =
72,
75,
84
---
Row 6 (dark blue circles):
Given: 90, __, 96, 99, 102, __
90 + 3 =
93 ← first blank
Check: 93 + 3 = 96 → correct
102 + 3 =
105 ← last blank
✔ Blanks =
93 and
105
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Now let’s list all the missing numbers in order as they appear in the worksheet:
Row 1: 12
Row 2: 21, 27
Row 3: 36, 51
Row 4: 60
Row 5: 72, 75, 84
Row 6: 93, 105
Final Answer:
12, 21, 27, 36, 51, 60, 72, 75, 84, 93, 105
Parent Tip: Review the logic above to help your child master the concept of counting by 3s worksheet.
