Answer:
4.21$
Explanation:
Because his total bill is 5.79$
If he pays with a 10$ bill meaning he get's 4.21$ back.
To calculate this we could subtract 5.79 by 10
Add to 5.79 lentil 10
Subtraction would look like this.
10.00$
5.79$
______
Since 0 can't subtract nine he goes to his neighbor 0 for help but he can't help so his neighbor 0 also goes for help to his neighbor 0 but he still can't help so then he goes to 1 and puts a 1 in front of 0 to make it 10
And then 0 that turned in to 10 helps other 0 to go to a 9 and it turn into 10 and then that 0 helps that least 0 to turn into 10.
So what's 10 -9=1
9-7=2 so now we got .21
And last to get out final number what is 9 - 5=4 and finally makes 4.21 and that's our answer.
Hope this helps have a great day:)