How did they calculate their estimates?

Mrs. McKinley's 4th Graders explained their estimate step by step:

"This was a great math problem for us. First we figured that if there were 2,215 envelopes processed after Day 1, and there are approximately 22 butterflies in each envelope, we came up with 48,730 butterflies processed after Day One. This took 7 hours, so we divided the number of butterflies by 87 to find out how many butterflies could be processed in 1 hour. We came up with approximately 560 each hour. We then went back to the first Day's information and knew that 4 people had spent 4 hours processing the envelopes. We multiplied 4 X 4 to get the first day's worth of work being 16 hours, and then we multiplied 16 hours by 560 butterflies each hour. We came up with 8,960 butterflies the first day, and added that to the 48,730 processed after Day 1. That gave us an estimated total of about 57,690 butterflies. If we rounded that off, it would be approximately 58,000 butterflies."

And Joan Raybourn's students also explained their calculation:

"First, we multiplied 2,215 by 22 and got 48,730. That is the number of butterflies fter the first day. Then we divided 2,215 by 87 to find that one person could process 25.5 envelopes in one hour. On day 1, 16 hours were spent processing, so 16 X 25.5 is 408 envelopes on Day 1. 408 X 22 gives us 8,976 butterflies. We added that to our original 48,730 to get our final answer."