adding 2quaters to 3 10-dollar bills and 7 dimes gives
we know that
1 quarter=$0.25
1 dime=$0.10
so
we have
2 quarters=2(0.25)=$0.50
3 10 dollar bills=3(10)=$30
7 dimes=7(0.10)=$0.70
Adds
0.50+30+0.70=$31.20
Thirty one dollars and twenty cents
Part 2
we have
5 10 dollar bills=$50
4 quarters=4(0.25)=$1
7 nikels=7(0.05)=$0.35
Adds
50+1+0.35=$51.35
Subtract 48.35 from 51.35
so
51.35-48.35=$3.00
answer is
$3.00 or three
Part 3
we have
1 50 dollar bill=$50
2 10 dollar bills=2(10)=$20
2 quarters=2(0.25)=$0.50
Adds
50+20+0.50=$70.50
Subtract 1 quarter
70.50-0.25=$70.25
therefore
the answer is
$70.25