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Arithmetic series worksheets Grades 11–12

Find the sum of an arithmetic series.

The front of the free arithmetic series worksheet
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Free · Worked example · 18 problems · Answer key · US Letter

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How to do it

Count the terms: n = (last − first) ÷ d + 1. Then Sₙ = n(a₁ + aₙ) ÷ 2.

−2−10−18+...−194=−2450-2 - 10 - 18 + ... - 194 = -2450
−194−(−2)−8+1=25\dfrac{-194 - (-2)}{-8} + 1 = 25how many terms: n = (last − first) ÷ d + 1
25(−2+(−194))2=−2450\dfrac{25(-2 + (-194))}{2} = -2450Sₙ = n(a₁ + aₙ) ÷ 2

Example problems

  1. 17+22+27+...+127=17 + 22 + 27 + ... + 127 =
  2. 12+13+14+...+30=12 + 13 + 14 + ... + 30 =
  3. −5−2+1+...+46=-5 - 2 + 1 + ... + 46 =
  4. 9+6+3+...−21=9 + 6 + 3 + ... - 21 =

Sequences and series

  1. Arithmetic sequences
  2. Geometric sequences
  3. Writing the formula for a sequence
  4. Sigma notation
  5. Arithmetic series
  6. Geometric series
  7. Infinite geometric series
  8. Combinations (nCk)
  9. The binomial theorem