What is the best way to estimate the number of coins in a coin jar? What strategy might you consider?
Do you know how many pennies are in these rolls? What assumptions are you making? What information do you need?
Helpful info
https://www.usmint.gov/kids/coinNews/circulating/01centCoin.html
http://lifehacker.com/5804773/quicklyestimatehowmuchmoneysinyourchangejarbyweight
The official weights of contemporary U.S. coins are as follows: –
Cent – 2.5 grams
Nickel – 5 grams
Dime – 2.27 grams
Quarter – 5.67 grams
Half Dollar – 11.34 grams
Dollar (SBA) – 8.1 grams
Let’s have a math chat! Leave me a response to this math happening.
What do you wonder about? 

What do you know or notice? 

What information do you need? 

What assumptions can you make? 

What math will you use to solve the problem? 