Worksheet Solutions: Fun with Numbers (Numbers 1 to 100)

Q1: Look at the numbers. Write the rule describing each.

(i) 12, 15, 18, 21, 24, 27, 30, 33
Ans: Start at 12. Add 3 each time.

Explanation:

We start with 12.

Then add 3 → 12 + 3 = 15

Add 3 again → 15 + 3 = 18
Keep adding 3 → 21, 24, 27, 30, 33

(ii) 45, 40, 35, 30, 25, 20, 15, 10
Ans: Start at 45. Subtract 5 each time.

Explanation:

We start with 45.

Then subtract 5 → 45 - 5 = 40

Subtract 5 again → 40 - 5 = 35

Keep subtracting 5 → 30, 25, 20, 15, 10

(iii) 6, 8, 10, 12, 14, 16, 18, 20
Ans: Start at 6. Add 2 each time.

Explanation:

Start with 6.

Then add 2 → 6 + 2 = 8

Add 2 again → 8 + 2 = 10

Keep adding 2 → 12, 14, 16, 18, 20

(iv) 20, 30, 40, 50, 60, 70, 80, 90
Ans: Start at 20. Add 10 each time.

Explanation:

Start with 20.

Then add 10 → 20 + 10 = 30

Add 10 again → 30 + 10 = 40

Keep adding 10 → 50, 60, 70, 80, 90

(v) 56, 49, 42, 35, 28, 21, 14, 7
Ans: Start at 56. Subtract 7 each time.

Explanation:

Start with 56.

Then subtract 7 → 56 - 7 = 49

Subtract 7 again → 49 - 7 = 42

Keep subtracting 7 → 35, 28, 21, 14, 7

(vi) 11, 22, 33, 44, 55, 66, 77, 88
Ans: Start at 11. Add 11 each time.

Explanation:

Start with 11.

Then add 11 → 11 + 11 = 22

Add 11 again → 22 + 11 = 33

Keep adding 11 → 44, 55, 66, 77, 88

(vii) 81, 72, 63, 54, 45, 36, 27, 18
Ans: Start at 81. Subtract 9 each time.

Explanation:

Start with 81.

Then subtract 9 → 81 - 9 = 72

Subtract 9 again → 72 - 9 = 63

Keep subtracting 9 → 54, 45, 36, 27, 18

(viii) 15, 19, 23, 27, 31, 35, 39, 43
Ans: Start at 15. Add 4 each time.

Explanation:

Start with 15.

Then add 4 → 15 + 4 = 19

Add 4 again → 19 + 4 = 23

Keep adding 4 → 27, 31, 35, 39, 43

(ix) 65, 62, 59, 56, 53, 50, 47, 44
Ans: Start at 65. Subtract 3 each time.

 Explanation:

Start with 65.

Then subtract 3 → 65 - 3 = 62

Subtract 3 again → 62 - 3 = 59

Keep subtracting 3 → 56, 53, 50, 47, 44

Q2: Describe the series followed by the hops in each number line.

(i)
Ans: Start at 48. Add 12 each time.

Explanation:

We begin at 48.

Add 12 → 48 + 12 = 60

Add 12 again → 60 + 12 = 72

Keep adding 12 → 84, 96

(ii)
Ans: Start at -19. Add 4 each time.

Explanation:

Start at -19 (a negative number).

Add 4 → -19 + 4 = -15

Add 4 again → -15 + 4 = -11

Keep adding 4 → -7, -3, 1

(iii)
Ans: Start at 80. Subtract 10 each time.

 Explanation:

Start with 80.

Subtract 10 → 80 - 10 = 70

Subtract 10 again → 70 - 10 = 60

Keep subtracting 10 → 50, 40, 30, 20

(iv)
Ans: Start at 6. Subtract 18 each time.

Explanation:

Start at 6.

Subtract 18 → 6 - 18 = -12

Subtract 18 again → -12 - 18 = -30

Keep subtracting 18 → -48, -66

(v)
Ans: Start at -10. Add 2 each time.

Explanation:

Start at -10.

Add 2 → -10 + 2 = -8

Add 2 again → -8 + 2 = -6

Keep adding 2 → -4, -2, 0, 2

(vi)
Ans: Start at 73. Subtract 8 each time.

Explanation:

Start at 73.

Subtract 8 → 73 - 8 = 65

Subtract 8 again → 65 - 8 = 57

Keep subtracting 8 → 49, 41, 33, 25

Q3: Identify the number sequence and fill in the missing numbers.

(i) 

Ans: 23, 30, 38, 47, 57

 Explanation:

• Start at 3
• Add 2 → 3 + 2 = 5
• Add 3 → 5 + 3 = 8
• Add 4 → 8 + 4 = 12
• Add 5 → 12 + 5 = 17
• Add 6 → 17 + 6 = 23
• Add 7 → 23 + 7 = 30
• Add 8 → 30 + 8 = 38
• Add 9 → 38 + 9 = 47
• Add 10 → 47 + 10 = 57

Pattern: The numbers are increasing by 2, 3, 4, 5, 6, etc.

(ii) 

Ans: 14, 7, -1, -10, -20

Explanation:

• Start at 34
• Subtract 2 → 34 - 2 = 32
• Subtract 3 → 32 - 3 = 29
• Subtract 4 → 29 - 4 = 25
• Subtract 5 → 25 - 5 = 20
  

• Subtract 6 → 14

• Subtract 7 → 7

• Subtract 8 → -1

• Subtract 9 → -10

Pattern: The numbers are decreasing by 2, 3, 4, 5, etc.

(iii) 

Ans: 50, 45, 41, 38, 36

Explanation:

• Start at 90
• Subtract 10 → 90 - 10 = 80
• Subtract 9 → 80 - 9 = 71
• Subtract 8 → 71 - 8 = 63
• Subtract 7 → 63 - 7 = 56
• Subtract 6  → 56 - 6  = 50
• Subtract 5 → 50 - 5 = 45
• ​Subtract 4 → 45 - 4 = 41
• ​Subtract 3 → 41 - 3 = 38
• ​Subtract 2 → 38 - 2 = 36

Pattern: The numbers are decreasing by 10, 9, 8, 7, etc.

(iv) 

Ans: -16, -12, -9, -7, -6

Explanation:

• Start at -50
• Add 8 → -50 + 8 = -42
• Add 8 → -42 + 8 = -34
• Add 7 → -34 + 7 = -27
• Add 6 → -27 + 6 = -21
• Add 5 → -21 + 5 = -16
• Add 4 → -16 + 4 = -12
• Add 3 → -12 + 3 = -9
• Add 2 → -9 + 2 = -7
• Add 1 → -7 + 1 = -6

Pattern: The numbers increase by 8, 8, 7, 6, 5, etc.

(v) 

Ans: 36, 44, 53, 63, 74

Explanation:

• Start at 11
• Add 3 → 11 + 3 = 14
• Add 4 → 14 + 4 = 18
• Add 5 → 18 + 5 = 23
• Add 6 → 23 + 6 = 29

• Add 7 → 29 + 7 = 36

• Add 8 → 36 + 8 = 44

• Add 9 → 44 + 9 = 53

• Add 10 → 53 + 10 = 63

• Add 11 → 63 + 11 = 74

Pattern: The numbers increase by 3, 4, 5, 6, etc.

(vi) 

Ans: 12, 18, 25, 33, 42

Explanation:

• Start at -3
• Add 1 → -3 + 1 = -2
• Add 2 → -2 + 2 = 0
• Add 3 → 0 + 3 = 3
• Add 4 → 3 + 4 = 7

• Add 5 → 7 + 5 = 12

• Add 6 → 12 + 6 = 18

• Add 7 → 18 + 7 = 25

• Add 8 → 25 + 8 = 33

• Add 9 → 33 + 9 = 42
  

Pattern: The numbers increase by 1, 2, 3, 4, etc.

Q4: Jumpy Frog Pattern

Observe how Jumpy, the frog, jumps along numbers 1 to 20 by counting in twos. If Jumpy starts at 1 and jumps +2 each time, which numbers will he land on? 
Write the first five:

____, ____, ____, ____, ____.

Ans: 1, 3, 5, 7, 9

Explanation:

1. Jumpy starts at 1.

2. Each jump adds 2 more to the number he is on.

3. To find the next number, start with 1 and keep adding 2:

• First number: 1

• Second number: 1 + 2 = 3

• Third number: 3 + 2 = 5

• Fourth number: 5 + 2 = 7

• Fifth number: 7 + 2 = 9

So, the first five numbers Jumpy lands on are:
1, 3, 5, 7, 9