Math worksheet on sequences featuring problems to find nth terms, 10th terms, and first four terms of linear sequences.
A math worksheet titled "Sequences" with three sections: finding the nth and 10th terms of linear sequences, finding the nth term of linear sequences with fractional increments, and finding the first four terms of sequences given their nth term formulas.
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Step-by-step solution for: GCSE MATHS sequences worksheet
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Show Answer Key & Explanations
Step-by-step solution for: GCSE MATHS sequences worksheet
Let’s solve each part step by step.
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Problem 1: Find the nᵗʰ and 10ᵗʰ term of the following linear sequences
A linear sequence has a constant difference between terms. The general formula is:
> nᵗʰ term = a + (n - 1)d
Where:
- `a` = first term
- `d` = common difference
- `n` = position in sequence
We’ll find `a`, `d`, then plug into the formula to get the nᵗʰ term, then substitute n=10 for the 10ᵗʰ term.
---
a) 6, 10, 14, 18, 22...
- a = 6
- d = 10 - 6 = 4
- nᵗʰ term = 6 + (n - 1)*4 = 6 + 4n - 4 = 4n + 2
- 10ᵗʰ term = 4*10 + 2 = 42
✔ Check: 6,10,14,18,22,26,30,34,38,42 → yes, 10th is 42.
---
b) 1, 6, 11, 16, 21...
- a = 1
- d = 5
- nᵗʰ term = 1 + (n - 1)*5 = 1 + 5n - 5 = 5n - 4
- 10ᵗʰ term = 5*10 - 4 = 46
✔ Check: 1,6,11,16,21,26,31,36,41,46 → correct.
---
c) 4, 6, 8, 10...
- a = 4
- d = 2
- nᵗʰ term = 4 + (n - 1)*2 = 4 + 2n - 2 = 2n + 2
- 10ᵗʰ term = 2*10 + 2 = 22
✔ Check: 4,6,8,10,12,14,16,18,20,22 → correct.
---
d) 13, 16, 19, 22, 25...
- a = 13
- d = 3
- nᵗʰ term = 13 + (n - 1)*3 = 13 + 3n - 3 = 3n + 10
- 10ᵗʰ term = 3*10 + 10 = 40
✔ Check: 13,16,19,22,25,28,31,34,37,40 → correct.
---
e) 7, 8, 9, 10, 11...
- a = 7
- d = 1
- nᵗʰ term = 7 + (n - 1)*1 = 7 + n - 1 = n + 6
- 10ᵗʰ term = 10 + 6 = 16
✔ Check: 7,8,9,10,11,12,13,14,15,16 → correct.
---
f) 1, 9, 17, 25...
Wait — let’s check differences:
9 - 1 = 8
17 - 9 = 8
25 - 17 = 8 → so d = 8
- a = 1
- d = 8
- nᵗʰ term = 1 + (n - 1)*8 = 1 + 8n - 8 = 8n - 7
- 10ᵗʰ term = 8*10 - 7 = 73
✔ Check: 1,9,17,25,33,41,49,57,65,73 → correct.
---
g) 2, 11, 20, 29, 38...
- a = 2
- d = 9
- nᵗʰ term = 2 + (n - 1)*9 = 2 + 9n - 9 = 9n - 7
- 10ᵗʰ term = 9*10 - 7 = 83
✔ Check: 2,11,20,29,38,47,56,65,74,83 → correct.
---
h) 5, 15, 25, 35, 45...
- a = 5
- d = 10
- nᵗʰ term = 5 + (n - 1)*10 = 5 + 10n - 10 = 10n - 5
- 10ᵗʰ term = 10*10 - 5 = 95
✔ Check: 5,15,25,35,45,55,65,75,85,95 → correct.
---
i) 0, 3, 6, 9, 12...
- a = 0
- d = 3
- nᵗʰ term = 0 + (n - 1)*3 = 3n - 3
- 10ᵗʰ term = 3*10 - 3 = 27
✔ Check: 0,3,6,9,12,15,18,21,24,27 → correct.
---
j) -1, 5, 11, 17, 23...
- a = -1
- d = 6
- nᵗʰ term = -1 + (n - 1)*6 = -1 + 6n - 6 = 6n - 7
- 10ᵗʰ term = 6*10 - 7 = 53
✔ Check: -1,5,11,17,23,29,35,41,47,53 → correct.
---
k) -3, 7, 17, 27, 37...
- a = -3
- d = 10
- nᵗʰ term = -3 + (n - 1)*10 = -3 + 10n - 10 = 10n - 13
- 10ᵗʰ term = 10*10 - 13 = 87
✔ Check: -3,7,17,27,37,47,57,67,77,87 → correct.
---
l) -10, -8, -6, -4...
- a = -10
- d = 2
- nᵗʰ term = -10 + (n - 1)*2 = -10 + 2n - 2 = 2n - 12
- 10ᵗʰ term = 2*10 - 12 = 8
✔ Check: -10,-8,-6,-4,-2,0,2,4,6,8 → correct.
---
Problem 2: Find the nᵗʰ term of the following linear sequences
Same method: find `a` and `d`, then use formula.
---
a) 12, 10, 8, 6, 4...
- a = 12
- d = -2
- nᵗʰ term = 12 + (n - 1)*(-2) = 12 - 2n + 2 = -2n + 14
✔ Check: n=1 → 12, n=2 → 10, n=3 → 8 → correct.
---
b) 3.5, 4, 4.5, 5, 5.5...
- a = 3.5
- d = 0.5
- nᵗʰ term = 3.5 + (n - 1)*0.5 = 3.5 + 0.5n - 0.5 = 0.5n + 3
Or write as fractions: ½n + 3
✔ Check: n=1 → 3.5, n=2 → 4 → correct.
---
c) 0.2, 0.4, 0.6, 0.8...
- a = 0.2
- d = 0.2
- nᵗʰ term = 0.2 + (n - 1)*0.2 = 0.2 + 0.2n - 0.2 = 0.2n
Or ⅕n
✔ Check: n=1 → 0.2, n=2 → 0.4 → correct.
---
d) 15, 12, 9, 6, 3...
- a = 15
- d = -3
- nᵗʰ term = 15 + (n - 1)*(-3) = 15 - 3n + 3 = -3n + 18
✔ Check: n=1 → 15, n=2 → 12 → correct.
---
e) ?, -4, -8, -12, -16...
First term missing. But we can see from second term onward:
From -4 to -8 → d = -4
So if term 2 is -4, then term 1 = -4 - (-4) = 0? Wait:
If d = -4, and term 2 = -4, then term 1 = term 2 - d = -4 - (-4) = 0
Check: 0, -4, -8, -12, -16 → yes!
So a = 0, d = -4
nᵗʰ term = 0 + (n - 1)*(-4) = -4n + 4
✔ Check: n=1 → 0, n=2 → -4 → correct.
---
f) 99, 98, 97, 96...
- a = 99
- d = -1
- nᵗʰ term = 99 + (n - 1)*(-1) = 99 - n + 1 = -n + 100
✔ Check: n=1 → 99, n=2 → 98 → correct.
---
Problem 3: Find the first 4 terms of each linear sequence whose nᵗʰ term is:
Just plug in n = 1, 2, 3, 4 into the given formula.
---
a) n + 6
- n=1 → 1+6 = 7
- n=2 → 2+6 = 8
- n=3 → 3+6 = 9
- n=4 → 4+6 = 10
→ 7, 8, 9, 10
---
b) n + 3
- n=1 → 4
- n=2 → 5
- n=3 → 6
- n=4 → 7
→ 4, 5, 6, 7
---
c) n - 5
- n=1 → -4
- n=2 → -3
- n=3 → -2
- n=4 → -1
→ -4, -3, -2, -1
---
d) n + 5
- n=1 → 6
- n=2 → 7
- n=3 → 8
- n=4 → 9
→ 6, 7, 8, 9
---
e) 4n - 3
- n=1 → 4(1)-3 = 1
- n=2 → 8-3 = 5
- n=3 → 12-3 = 9
- n=4 → 16-3 = 13
→ 1, 5, 9, 13
---
f) 8n + 11
- n=1 → 8+11 = 19
- n=2 → 16+11 = 27
- n=3 → 24+11 = 35
- n=4 → 32+11 = 43
→ 19, 27, 35, 43
---
g) 6n - 6
- n=1 → 6-6 = 0
- n=2 → 12-6 = 6
- n=3 → 18-6 = 12
- n=4 → 24-6 = 18
→ 0, 6, 12, 18
---
h) 5n
- n=1 → 5
- n=2 → 10
- n=3 → 15
- n=4 → 20
→ 5, 10, 15, 20
---
i) -3n + 24
- n=1 → -3+24 = 21
- n=2 → -6+24 = 18
- n=3 → -9+24 = 15
- n=4 → -12+24 = 12
→ 21, 18, 15, 12
---
All done! Let me now compile the final answers clearly.
Final Answer:
Problem 1:
a) nᵗʰ: 4n + 2; 10ᵗʰ: 42
b) nᵗʰ: 5n - 4; 10ᵗʰ: 46
c) nᵗʰ: 2n + 2; 10ᵗʰ: 22
d) nᵗʰ: 3n + 10; 10ᵗʰ: 40
e) nᵗʰ: n + 6; 10ᵗʰ: 16
f) nᵗʰ: 8n - 7; 10ᵗʰ: 73
g) nᵗʰ: 9n - 7; 10ᵗʰ: 83
h) nᵗʰ: 10n - 5; 10ᵗʰ: 95
i) nᵗʰ: 3n - 3; 10ᵗʰ: 27
j) nᵗʰ: 6n - 7; 10ᵗʰ: 53
k) nᵗʰ: 10n - 13; 10ᵗʰ: 87
l) nᵗʰ: 2n - 12; 10ᵗʰ: 8
Problem 2:
a) -2n + 14
b) 0.5n + 3 (or ½n + 3)
c) 0.2n (or ⅕n)
d) -3n + 18
e) -4n + 4
f) -n + 100
Problem 3:
a) 7, 8, 9, 10
b) 4, 5, 6, 7
c) -4, -3, -2, -1
d) 6, 7, 8, 9
e) 1, 5, 9, 13
f) 19, 27, 35, 43
g) 0, 6, 12, 18
h) 5, 10, 15, 20
i) 21, 18, 15, 12
---
Problem 1: Find the nᵗʰ and 10ᵗʰ term of the following linear sequences
A linear sequence has a constant difference between terms. The general formula is:
> nᵗʰ term = a + (n - 1)d
Where:
- `a` = first term
- `d` = common difference
- `n` = position in sequence
We’ll find `a`, `d`, then plug into the formula to get the nᵗʰ term, then substitute n=10 for the 10ᵗʰ term.
---
a) 6, 10, 14, 18, 22...
- a = 6
- d = 10 - 6 = 4
- nᵗʰ term = 6 + (n - 1)*4 = 6 + 4n - 4 = 4n + 2
- 10ᵗʰ term = 4*10 + 2 = 42
✔ Check: 6,10,14,18,22,26,30,34,38,42 → yes, 10th is 42.
---
b) 1, 6, 11, 16, 21...
- a = 1
- d = 5
- nᵗʰ term = 1 + (n - 1)*5 = 1 + 5n - 5 = 5n - 4
- 10ᵗʰ term = 5*10 - 4 = 46
✔ Check: 1,6,11,16,21,26,31,36,41,46 → correct.
---
c) 4, 6, 8, 10...
- a = 4
- d = 2
- nᵗʰ term = 4 + (n - 1)*2 = 4 + 2n - 2 = 2n + 2
- 10ᵗʰ term = 2*10 + 2 = 22
✔ Check: 4,6,8,10,12,14,16,18,20,22 → correct.
---
d) 13, 16, 19, 22, 25...
- a = 13
- d = 3
- nᵗʰ term = 13 + (n - 1)*3 = 13 + 3n - 3 = 3n + 10
- 10ᵗʰ term = 3*10 + 10 = 40
✔ Check: 13,16,19,22,25,28,31,34,37,40 → correct.
---
e) 7, 8, 9, 10, 11...
- a = 7
- d = 1
- nᵗʰ term = 7 + (n - 1)*1 = 7 + n - 1 = n + 6
- 10ᵗʰ term = 10 + 6 = 16
✔ Check: 7,8,9,10,11,12,13,14,15,16 → correct.
---
f) 1, 9, 17, 25...
Wait — let’s check differences:
9 - 1 = 8
17 - 9 = 8
25 - 17 = 8 → so d = 8
- a = 1
- d = 8
- nᵗʰ term = 1 + (n - 1)*8 = 1 + 8n - 8 = 8n - 7
- 10ᵗʰ term = 8*10 - 7 = 73
✔ Check: 1,9,17,25,33,41,49,57,65,73 → correct.
---
g) 2, 11, 20, 29, 38...
- a = 2
- d = 9
- nᵗʰ term = 2 + (n - 1)*9 = 2 + 9n - 9 = 9n - 7
- 10ᵗʰ term = 9*10 - 7 = 83
✔ Check: 2,11,20,29,38,47,56,65,74,83 → correct.
---
h) 5, 15, 25, 35, 45...
- a = 5
- d = 10
- nᵗʰ term = 5 + (n - 1)*10 = 5 + 10n - 10 = 10n - 5
- 10ᵗʰ term = 10*10 - 5 = 95
✔ Check: 5,15,25,35,45,55,65,75,85,95 → correct.
---
i) 0, 3, 6, 9, 12...
- a = 0
- d = 3
- nᵗʰ term = 0 + (n - 1)*3 = 3n - 3
- 10ᵗʰ term = 3*10 - 3 = 27
✔ Check: 0,3,6,9,12,15,18,21,24,27 → correct.
---
j) -1, 5, 11, 17, 23...
- a = -1
- d = 6
- nᵗʰ term = -1 + (n - 1)*6 = -1 + 6n - 6 = 6n - 7
- 10ᵗʰ term = 6*10 - 7 = 53
✔ Check: -1,5,11,17,23,29,35,41,47,53 → correct.
---
k) -3, 7, 17, 27, 37...
- a = -3
- d = 10
- nᵗʰ term = -3 + (n - 1)*10 = -3 + 10n - 10 = 10n - 13
- 10ᵗʰ term = 10*10 - 13 = 87
✔ Check: -3,7,17,27,37,47,57,67,77,87 → correct.
---
l) -10, -8, -6, -4...
- a = -10
- d = 2
- nᵗʰ term = -10 + (n - 1)*2 = -10 + 2n - 2 = 2n - 12
- 10ᵗʰ term = 2*10 - 12 = 8
✔ Check: -10,-8,-6,-4,-2,0,2,4,6,8 → correct.
---
Problem 2: Find the nᵗʰ term of the following linear sequences
Same method: find `a` and `d`, then use formula.
---
a) 12, 10, 8, 6, 4...
- a = 12
- d = -2
- nᵗʰ term = 12 + (n - 1)*(-2) = 12 - 2n + 2 = -2n + 14
✔ Check: n=1 → 12, n=2 → 10, n=3 → 8 → correct.
---
b) 3.5, 4, 4.5, 5, 5.5...
- a = 3.5
- d = 0.5
- nᵗʰ term = 3.5 + (n - 1)*0.5 = 3.5 + 0.5n - 0.5 = 0.5n + 3
Or write as fractions: ½n + 3
✔ Check: n=1 → 3.5, n=2 → 4 → correct.
---
c) 0.2, 0.4, 0.6, 0.8...
- a = 0.2
- d = 0.2
- nᵗʰ term = 0.2 + (n - 1)*0.2 = 0.2 + 0.2n - 0.2 = 0.2n
Or ⅕n
✔ Check: n=1 → 0.2, n=2 → 0.4 → correct.
---
d) 15, 12, 9, 6, 3...
- a = 15
- d = -3
- nᵗʰ term = 15 + (n - 1)*(-3) = 15 - 3n + 3 = -3n + 18
✔ Check: n=1 → 15, n=2 → 12 → correct.
---
e) ?, -4, -8, -12, -16...
First term missing. But we can see from second term onward:
From -4 to -8 → d = -4
So if term 2 is -4, then term 1 = -4 - (-4) = 0? Wait:
If d = -4, and term 2 = -4, then term 1 = term 2 - d = -4 - (-4) = 0
Check: 0, -4, -8, -12, -16 → yes!
So a = 0, d = -4
nᵗʰ term = 0 + (n - 1)*(-4) = -4n + 4
✔ Check: n=1 → 0, n=2 → -4 → correct.
---
f) 99, 98, 97, 96...
- a = 99
- d = -1
- nᵗʰ term = 99 + (n - 1)*(-1) = 99 - n + 1 = -n + 100
✔ Check: n=1 → 99, n=2 → 98 → correct.
---
Problem 3: Find the first 4 terms of each linear sequence whose nᵗʰ term is:
Just plug in n = 1, 2, 3, 4 into the given formula.
---
a) n + 6
- n=1 → 1+6 = 7
- n=2 → 2+6 = 8
- n=3 → 3+6 = 9
- n=4 → 4+6 = 10
→ 7, 8, 9, 10
---
b) n + 3
- n=1 → 4
- n=2 → 5
- n=3 → 6
- n=4 → 7
→ 4, 5, 6, 7
---
c) n - 5
- n=1 → -4
- n=2 → -3
- n=3 → -2
- n=4 → -1
→ -4, -3, -2, -1
---
d) n + 5
- n=1 → 6
- n=2 → 7
- n=3 → 8
- n=4 → 9
→ 6, 7, 8, 9
---
e) 4n - 3
- n=1 → 4(1)-3 = 1
- n=2 → 8-3 = 5
- n=3 → 12-3 = 9
- n=4 → 16-3 = 13
→ 1, 5, 9, 13
---
f) 8n + 11
- n=1 → 8+11 = 19
- n=2 → 16+11 = 27
- n=3 → 24+11 = 35
- n=4 → 32+11 = 43
→ 19, 27, 35, 43
---
g) 6n - 6
- n=1 → 6-6 = 0
- n=2 → 12-6 = 6
- n=3 → 18-6 = 12
- n=4 → 24-6 = 18
→ 0, 6, 12, 18
---
h) 5n
- n=1 → 5
- n=2 → 10
- n=3 → 15
- n=4 → 20
→ 5, 10, 15, 20
---
i) -3n + 24
- n=1 → -3+24 = 21
- n=2 → -6+24 = 18
- n=3 → -9+24 = 15
- n=4 → -12+24 = 12
→ 21, 18, 15, 12
---
All done! Let me now compile the final answers clearly.
Final Answer:
Problem 1:
a) nᵗʰ: 4n + 2; 10ᵗʰ: 42
b) nᵗʰ: 5n - 4; 10ᵗʰ: 46
c) nᵗʰ: 2n + 2; 10ᵗʰ: 22
d) nᵗʰ: 3n + 10; 10ᵗʰ: 40
e) nᵗʰ: n + 6; 10ᵗʰ: 16
f) nᵗʰ: 8n - 7; 10ᵗʰ: 73
g) nᵗʰ: 9n - 7; 10ᵗʰ: 83
h) nᵗʰ: 10n - 5; 10ᵗʰ: 95
i) nᵗʰ: 3n - 3; 10ᵗʰ: 27
j) nᵗʰ: 6n - 7; 10ᵗʰ: 53
k) nᵗʰ: 10n - 13; 10ᵗʰ: 87
l) nᵗʰ: 2n - 12; 10ᵗʰ: 8
Problem 2:
a) -2n + 14
b) 0.5n + 3 (or ½n + 3)
c) 0.2n (or ⅕n)
d) -3n + 18
e) -4n + 4
f) -n + 100
Problem 3:
a) 7, 8, 9, 10
b) 4, 5, 6, 7
c) -4, -3, -2, -1
d) 6, 7, 8, 9
e) 1, 5, 9, 13
f) 19, 27, 35, 43
g) 0, 6, 12, 18
h) 5, 10, 15, 20
i) 21, 18, 15, 12
Parent Tip: Review the logic above to help your child master the concept of sequences worksheet year 7.