Give the step-by-step reasoning process and then the final answer. Randy had 32 biscuits. His father gave him 13 biscuits as a gift. His mother gave him 15 biscuits. Randy's brother ate 20 of these biscuits. How many biscuits are Randy left with?
After his father gave him 13 biscuits, Randy has 32 + 13 = 45 biscuits. After his mother gave him 15 biscuits, Randy has 45 + 15 = 60 biscuits. After his brother ate 20 of the biscuits. Randy has 60 20 = 40 biscuits.
The final answer: 40.