an hour a day goes a long way
hom.classspace.io
Hour of Math · SS1 · Unit FMP6
Derive S_n = n/2 (a + l) by pairing, use S_n = n/2 [2a + (n - 1)d], work backwards from a sum to n, d or a, and solve three-term and real-world problems with arithmetic series.
Loading lesson…