Grade 10 · Math
Sum an arithmetic sequence practice
Use equal-sum pairs to find a finite arithmetic series.
Opening your practice adventure…
Try a sample
Find the sum of the first 6 terms of an arithmetic sequence whose first term is 8 and common difference is 3.
- 93
- 92
- 95
- 94
See the answer & why
93
The last term is 23. Sum = 6(8+23)/2 = 93.
A little hint: Pair the first and last terms; each pair has the same total.
A teaching tip
Find the last term, average the first and last, then multiply by the number of terms.