Question: If the typical monarch weighs 500 mg, how much would a branch loaded with 15,000 butterflies weigh? (Give your answer in kilograms and in pounds.) Also name another object that weighs the same amount, for comparison.

Answer: The butterflies would weigh 7.5 kilograms (or 16.5 pounds).

Sixteen pounds of monarchs weigh as much as 1,280 pencils! (Ms. Cottrell's Class in Mississippi found that 80 new pencils would weigh about one pound, so multiply by 16 to get 1,280.)

Thanks to these students for sharing their math:

Mr. Kegelmayer's 3rd grade class from Columbus Academy in Gahanna, Ohio. "The answer to how much the branch weighs loaded with butterflies is 7.5 kilograms."

Mrs. Kane's second grade class at Brookside Elementary School in Binghamton, NY thinks the answer to challenge question #2 for the Monarch Migration would be 16.5 pounds and 7.5 milligrams.

Nathaniel Home School in VA says 7.5 kilograms or 16.5 pounds.

Mrs. Busher's 3rd grade students at Cloverdale Elementary in Virginia did the math. "We decided that there are 7.5 kg or 16.5 lbs. of butterflies on a branch!"

The students in Mrs. Busher's 3rd grade Young Scholars of Botetourt County Schools in Fincastle, VA. think that the weight of the butterflies on a branch is 7.5 kg or 16.53 lbs.

Mrs. Ford's class from Parkway School District, St. Louis, MO We think 15,000 butterflies would weight 7,500 grams or 16.5 pounds.

Ms. Cottrell's Class at Poplarville Upper Elementary, MS converted milligrams to pounds. We found out that 1,000 mg= 0.002 pounds. Half of 1,000 mg is 500mg. 500 mg would be 0.001 pounds. There are 15,000 Monarchs on a branch. Each monarch weighs 0.001 pounds. 15,000x0.001 is 15. They would weigh 15 pounds. We found out that 5 new pencils weigh about one ounce. There are 16 ounces in a pound. 80 new pencils would weigh about one pound.