Verified Answer :

A penny is worth 1 cents. So, 84 pennies is 84 cents or $0.84
A dime is worth 10 cents, So, 300 dimes is 30 dollars or $
30 dollars

$0.84 + $30 = $30.84
84 pennies and 300 dimes is equivalent to 30 dollars and 84 cents.

300 dimes = $30.00
so.....You have $
30.00, then you add 84 centsĀ 
add themĀ together and you have $30.84