Question

Find the missing term of the arithmetic sequence 20, ___ , 32, ….

Answer 1

32-20=12
12/2=6

Add 6 to the first number.

Answer 2

or looking at it a slightly different way, if the common difference is \(d\), our sequence is
\[20, 20+d, 32\]or\[20, 20+d, 20+d+d\]and \[20+d+d=32\]
Easy enough to solve that for the value of \(d\), right?