Ok so we know he used over 700 because he was charged more than 40. Then we take the $8.10 and divide 0.45 into it. This then gives you 18 more minutes. Then add 18 to 700 and you get 718 min.
Your multiplying by -4 each time
-1x-4=4
4x-4=-16
-16x-4=64
you just have to move the decimal point 9 places to the right thats an easy trick to remember 1849900000
If the dolphins are fed half a bucket of fish then half of that would be a quarter, therefore the sea otters are fed 1/4 of a bucket.
