3. Here are students describing how they mentally computed 85% of 180: 1. "50% of 180 is 90. Half of that must be 25% of 180. So adding 90 to half of 90, 45, is 135. That is 75% of 180. 10% of 180 is easy, that's 18. So 85% of 180 is the sum 135 and 18, it's 153." 2. "10% of 180 is 18, so 5% of 180 must be half of that, 9. So, if I take 15% of 180 away from 180, I need to subtract 18 plus 9, that's 27. So 180 minus 20 is 160. Minus 7 more is 153, that's 85% of 180." a. Use a mental strategy to find 45% of 180 and describe the process in a manner similar to what the students did (but use more college-y language). b. Use a mental strategy to find 75% of 104