Question

# Subtract $12hr$ $58min$ from $20hr$ $5min$.

Hint: Convert $20hr$ $5min$ in such a way that it is easier to subtract the other entity with it.

$20hr + 5\min = 19hr + 1hr + 5\min$
We can write $1hr$ as $60mins$,
$20hr + 5mins$ = $19hr + 65mins$
$19hr$ $65mins$ - $12hrs$ $58min$
$Answer$ = $7hrs$ $7mins$