Strategy #4: Apply Percent Change Formula Correctly

Percent change = (New − Old) / Old × 100. Students commonly divide by the new value instead of the old, which is the single most frequent arithmetic error on SAT percent problems. If a price increases from $80 to $100, the percent increase is (100 − 80)/80 = 25%, not 20%.

💡 Practice tip: Always identify the "starting" value first and put it in the denominator. Circle it before writing the fraction.