Classroom Tools: Coin problem calculation instructions

Secrets of Good Lessons
Make the Familiar Strange or the Strange Familiar

Instructions for calculating a solution to the coin problem

U.S. coins

	Weight	Thickness	Diameter
	grams	mm	mm
	=======	=========	========
Penny (1959-82)	3.11	1.55	19.05
Penny (since 1983)	2.5	1.55	19.05
Nickel	5	1.95	21.21
Dime (through 1964)	2.5	1.35	17.91
Dime (since 1965)	2.268	1.35	17.91
Quarter (through 1964)	6.25	1.75	24.26
Quarter (since 1965)	5.67	1.75	24.26

1 inch=25.4 mm 1 pound=453.59237 grams

To determine an answer for a specific student

1. for the person's weight

a. Multiply 453.59237 (the # of grams in 1 pound) by the person's weight
b. Divide the answer from a. by the weight of the coin in grams
c. Divide the answer from b. by the number of coins in one dollar
d. Round the answer from c. to the nearest penny

2. for the person's height with the coins stacked

a. Multiply the number of feet tall by 12 then add the number of inches
b. Multiply the answer from a. by 25.4 (the number of millimeters in one inch)
c. Divide the answer from b. by the thickness of the coin in millimeters
d. Divide the answer from c. by the number of coins in one dollar
e. Round the answer from d. to the nearest penny

3. for the person's height with the coins laid edge to edge

a. Multiply the number of feet tall by 12 then add the number of inches
b. Multiply the answer from a. by 25.4 (the number of millimeters in one inch)
c. Divide the answer from b. by the diameter of the coin in millimeters
d. Divide the answer from c. by the number of coins in one dollar
e. Round the answer from d. to the nearest penny

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