Question: how many 7 in 1 to 200?
Answer: Between 1 and 100 : 7, 17, 27, 37, 47, 57, 67, 70, 71, 72, 73, 74, 75, 79, 77 (two sevens), 78, 79, 87, 97. Similarly, 20 sevens between 101 to 200.