math
posted by IVAN .
FIND THE ELAPSED TIME
START 1:43
FINISH 6:20
HOW DO I FIND IT

6:30  1:43
You need to change 6:30 to 5:90 then subtract.
5:90  1:43 = ?
We'll be glad to check your answer. 
4 HR AND 47 MIN, WHAT I DON'T UNDERSTAND IS WHY DO I CHANGE 6:30 to 5:90, thank you Ms.Sue

You're welcome. Your answer is right. :)
The easiest way to subtract 1:43 from 6:30 is to change 6:30 to 5:90 because you can't take 43 from 30 without borrowing.
Thirty minutes after six is the same as 90 minutes after five.