MathsAges 16-18

Arithmetic series sum

Sum the first n terms of an arithmetic progression using Sₙ = (n ÷ 2)(2a + (n − 1)d). Review suitability for your learners before teaching.

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Worksheet StudioPractice pack · Ages 16-18

Arithmetic series sum

Take your time. Show your thinking.

1. Find the sum of the first 6 terms of the arithmetic series with first term a = 11 and common difference d = 2.
6 · 11 · 2 · Arithmetic series sum
2. Find the sum of the first 14 terms of the arithmetic series with first term a = 12 and common difference d = 4.
14 · 12 · 4 · Arithmetic series sum
3. Find the sum of the first 12 terms of the arithmetic series with first term a = 8 and common difference d = 2.
12 · 8 · 2 · Arithmetic series sum
4. Find the sum of the first 10 terms of the arithmetic series with first term a = 13 and common difference d = 5.
10 · 13 · 5 · Arithmetic series sum
5. Find the sum of the first 14 terms of the arithmetic series with first term a = 1 and common difference d = 9.
14 · 1 · 9 · Arithmetic series sum
6. Find the sum of the first 8 terms of the arithmetic series with first term a = 12 and common difference d = 5.
8 · 12 · 5 · Arithmetic series sum
7. Find the sum of the first 4 terms of the arithmetic series with first term a = 5 and common difference d = 2.
4 · 5 · 2 · Arithmetic series sum
8. Find the sum of the first 6 terms of the arithmetic series with first term a = 8 and common difference d = 6.
6 · 8 · 6 · Arithmetic series sum
9. Find the sum of the first 8 terms of the arithmetic series with first term a = 5 and common difference d = 2.
8 · 5 · 2 · Arithmetic series sum
10. Find the sum of the first 4 terms of the arithmetic series with first term a = 12 and common difference d = 2.
4 · 12 · 2 · Arithmetic series sum
11. Find the sum of the first 14 terms of the arithmetic series with first term a = 9 and common difference d = 2.
14 · 9 · 2 · Arithmetic series sum
12. Find the sum of the first 6 terms of the arithmetic series with first term a = 5 and common difference d = 9.
6 · 5 · 9 · Arithmetic series sum

12 questions · Seed 104732 · Age guidance, not curriculum certification

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Worksheet StudioAnswer key · Ages 16-18

Arithmetic series sum

Answers and reasoning. Review before teaching.

1. Find the sum of the first 6 terms of the arithmetic series with first term a = 11 and common difference d = 2.
96
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (6 ÷ 2)(2 × 11 + 5 × 2) = 96.
2. Find the sum of the first 14 terms of the arithmetic series with first term a = 12 and common difference d = 4.
532
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (14 ÷ 2)(2 × 12 + 13 × 4) = 532.
3. Find the sum of the first 12 terms of the arithmetic series with first term a = 8 and common difference d = 2.
228
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (12 ÷ 2)(2 × 8 + 11 × 2) = 228.
4. Find the sum of the first 10 terms of the arithmetic series with first term a = 13 and common difference d = 5.
355
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (10 ÷ 2)(2 × 13 + 9 × 5) = 355.
5. Find the sum of the first 14 terms of the arithmetic series with first term a = 1 and common difference d = 9.
833
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (14 ÷ 2)(2 × 1 + 13 × 9) = 833.
6. Find the sum of the first 8 terms of the arithmetic series with first term a = 12 and common difference d = 5.
236
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (8 ÷ 2)(2 × 12 + 7 × 5) = 236.
7. Find the sum of the first 4 terms of the arithmetic series with first term a = 5 and common difference d = 2.
32
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (4 ÷ 2)(2 × 5 + 3 × 2) = 32.
8. Find the sum of the first 6 terms of the arithmetic series with first term a = 8 and common difference d = 6.
138
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (6 ÷ 2)(2 × 8 + 5 × 6) = 138.
9. Find the sum of the first 8 terms of the arithmetic series with first term a = 5 and common difference d = 2.
96
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (8 ÷ 2)(2 × 5 + 7 × 2) = 96.
10. Find the sum of the first 4 terms of the arithmetic series with first term a = 12 and common difference d = 2.
60
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (4 ÷ 2)(2 × 12 + 3 × 2) = 60.
11. Find the sum of the first 14 terms of the arithmetic series with first term a = 9 and common difference d = 2.
308
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (14 ÷ 2)(2 × 9 + 13 × 2) = 308.
12. Find the sum of the first 6 terms of the arithmetic series with first term a = 5 and common difference d = 9.
165
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (6 ÷ 2)(2 × 5 + 5 × 9) = 165.

12 questions · Seed 104732 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 16-18

Arithmetic series sum

Take your time. Show your thinking.

1. Find the sum of the first 6 terms of the arithmetic series with first term a = 11 and common difference d = 2.
6 · 11 · 2 · Arithmetic series sum
2. Find the sum of the first 14 terms of the arithmetic series with first term a = 12 and common difference d = 4.
14 · 12 · 4 · Arithmetic series sum
3. Find the sum of the first 12 terms of the arithmetic series with first term a = 8 and common difference d = 2.
12 · 8 · 2 · Arithmetic series sum
4. Find the sum of the first 10 terms of the arithmetic series with first term a = 13 and common difference d = 5.
10 · 13 · 5 · Arithmetic series sum
5. Find the sum of the first 14 terms of the arithmetic series with first term a = 1 and common difference d = 9.
14 · 1 · 9 · Arithmetic series sum
6. Find the sum of the first 8 terms of the arithmetic series with first term a = 12 and common difference d = 5.
8 · 12 · 5 · Arithmetic series sum
7. Find the sum of the first 4 terms of the arithmetic series with first term a = 5 and common difference d = 2.
4 · 5 · 2 · Arithmetic series sum
8. Find the sum of the first 6 terms of the arithmetic series with first term a = 8 and common difference d = 6.
6 · 8 · 6 · Arithmetic series sum
9. Find the sum of the first 8 terms of the arithmetic series with first term a = 5 and common difference d = 2.
8 · 5 · 2 · Arithmetic series sum
10. Find the sum of the first 4 terms of the arithmetic series with first term a = 12 and common difference d = 2.
4 · 12 · 2 · Arithmetic series sum
11. Find the sum of the first 14 terms of the arithmetic series with first term a = 9 and common difference d = 2.
14 · 9 · 2 · Arithmetic series sum
12. Find the sum of the first 6 terms of the arithmetic series with first term a = 5 and common difference d = 9.
6 · 5 · 9 · Arithmetic series sum

12 questions · Seed 104732 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 16-18

Arithmetic series sum

Answers and reasoning. Review before teaching.

1. Find the sum of the first 6 terms of the arithmetic series with first term a = 11 and common difference d = 2.
96
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (6 ÷ 2)(2 × 11 + 5 × 2) = 96.
2. Find the sum of the first 14 terms of the arithmetic series with first term a = 12 and common difference d = 4.
532
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (14 ÷ 2)(2 × 12 + 13 × 4) = 532.
3. Find the sum of the first 12 terms of the arithmetic series with first term a = 8 and common difference d = 2.
228
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (12 ÷ 2)(2 × 8 + 11 × 2) = 228.
4. Find the sum of the first 10 terms of the arithmetic series with first term a = 13 and common difference d = 5.
355
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (10 ÷ 2)(2 × 13 + 9 × 5) = 355.
5. Find the sum of the first 14 terms of the arithmetic series with first term a = 1 and common difference d = 9.
833
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (14 ÷ 2)(2 × 1 + 13 × 9) = 833.
6. Find the sum of the first 8 terms of the arithmetic series with first term a = 12 and common difference d = 5.
236
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (8 ÷ 2)(2 × 12 + 7 × 5) = 236.
7. Find the sum of the first 4 terms of the arithmetic series with first term a = 5 and common difference d = 2.
32
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (4 ÷ 2)(2 × 5 + 3 × 2) = 32.
8. Find the sum of the first 6 terms of the arithmetic series with first term a = 8 and common difference d = 6.
138
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (6 ÷ 2)(2 × 8 + 5 × 6) = 138.
9. Find the sum of the first 8 terms of the arithmetic series with first term a = 5 and common difference d = 2.
96
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (8 ÷ 2)(2 × 5 + 7 × 2) = 96.
10. Find the sum of the first 4 terms of the arithmetic series with first term a = 12 and common difference d = 2.
60
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (4 ÷ 2)(2 × 12 + 3 × 2) = 60.
11. Find the sum of the first 14 terms of the arithmetic series with first term a = 9 and common difference d = 2.
308
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (14 ÷ 2)(2 × 9 + 13 × 2) = 308.
12. Find the sum of the first 6 terms of the arithmetic series with first term a = 5 and common difference d = 9.
165
Sₙ = (n ÷ 2)(2a + (n − 1)d) = (6 ÷ 2)(2 × 5 + 5 × 9) = 165.

12 questions · Seed 104732 · Age guidance, not curriculum certification