Cleo and Ignacio placed 30 of their marbles in a jar on a Monday. They took 3/5 of the marbles from the jar the next day and divided them equally. On the third day, Cleo took 1/2 of the marbles remaining in the jars. How many marbles did Cleo have on the third day? Give the rationale and then the answer.
Let's think step by step. On the first day, Cleo and Ignacio took 3 / 5 * 30 marbles = 18 marbles from the jar. When they shared the marbles, each got 18 marbles / 2 people = 9 marbles / person. The total number of marbles remaining in the jar is 30 marbles - 18 marbles = 12 marbles. On the third day, Cleo took 1 / 2 * 12 marbles = 6 marbles from the jar. The total number of marbles she has on the third day is 6 marbles + 9 marbles = 15 marbles.. The answer is: 15.

There were 37 jellybeans in a jar. Pat removed 15 of them. Pat then added 5 of the removed jellybeans back in, and then removed 4 more. How many jellybeans are now in the jar? Give the rationale and then the answer.
Let's think step by step. After removing 15 jellybeans, there were 37 - 15 = 22 jellybeans in the jar. After adding back 5 jellybeans, there were 22 + 5 = 27 jellybeans in the jar. After removing 4 more jellybeans, there were 27 - 4 = 23 jellybeans left in the jar.. The answer is: 23.

Mike is feeding the birds at the park. He counts out the seeds as he throws them. He throws 20 seeds to the birds on the left. He throws twice as much to the bigger group of birds on the right. Some more birds flutter over to join the others for lunch and Mike throws 30 more seeds for them. If Mike has 30 seeds left to feed the last of the birds, how many seeds did Mike start with? Give the rationale and then the answer.
Let's think step by step. Mike started by throwing 20 seeds to the birds and then threw twice as many, 20 + 20(2) = 20 + 40. That totals to 20 + 40 = 60 seeds. He also threw 30 other seeds and had 30 left over, which means he started with 60 + 30 + 30 = 120 seeds.. The answer is: 120.