Class 10 · Chapter 5 · Algebra

Arithmetic Progressions

Lists that change by the same step every time.

Source: NCERT Mathematics, Class 10

1. 5.1What Makes a List an APAttention · Look at the gaps between the terms, not at the terms.8 min
2. 5.2The Common Difference and Its SignAttention · Look at the order of the subtraction: the later term comes first.8 min
3. 5.3The nth TermAttention · Look at (n − 1): it counts jumps, not terms.10 min
4. 5.4Is It a Term?Attention · Look at what kind of number n turns out to be.10 min
5. 5.5Sum of the First n TermsAttention · Look at the bracket: it is one pair, the first term plus the last.12 min
6. 5.6From Sums Back to TermsAttention · Look at how much the total grew: that growth is the newest term.8 min