This is percent of change
15 yards to 18 yards
100 acres to 140 acres
$15.60 to 18 yards
125 centimeters to 87.5 centimeters
1.6 hours to 0.95 hour
and
132 days to 125.4 days
i was just wondering because so i could check my answers

15 --> 18 is a percentage of 18/15*100 which is 120, so it's a 20% increase. Do the same for the rest:
100 to 140 is a 40% increase
"$15.60 to 18 yards" that doesn't make sense
125 to 87.5 is a 30% decrease
1.6 to 0.95 is a 40.625% decrease.
132 to 125.4 is a 5% decrease.

For the working, you do (first number/second number)*100 and then work out what it's gone up or down by. If it's more than 100, do that number -100, if it's less than 100 do 100-that number.