First of all I don't believe she could join the small pieces. What with? Glue? But the dried glue wouldn't write on the board. J Maybe she puts them in a special tube that holds them straight. Does she use exactly 1 full stick each day? Or onlyths of a stick each day? In other words, does she have to get a new stick before the end of each day? If she uses ths of a stick every day, and puts aside the to join, then we divide 49 pieces by 6/7 pieces per day to find out how many days. 49÷ = ÷ = × = = days. However if she uses exactly 1 complete stick of chalk each day, then it doesn't matter how she pieces them together. So if she uses exactly 1 piece per day, the 49 sticks will last her 49 days. This may be just a trick question, and the answer is just 49, regardless of how much chalk-piece joining she does. Edwin