To answer the question, you need to count backwards from 15 to 6 and add up the pieces of chalk. 15+14+13+12+11+10+9+8+7+6=105. That means there are 105 pieces of chalk in the pile. Hope this helps.
Answer:
-9
Step-by-step explanation:
-30 + 16 is -14 then -14 - 7 is -21 then -21 +3 is -18 then -18 + 9 is -9