Solve a problem

PercentagesArithmeticMiddle schoolabout 0:29

Percent change from 50 to 40: animated lesson

A narrated, step-by-step percentages video lesson with captions. Final answer: -20% (decrease).

SpeedLanguage

Video with a synthetic English voice and captions. Pick another language for subtitles in that language, or open the interactive version.

Video narrated by a synthetic voice (Piper TTS, en_US-ljspeech-high voice (LJ Speech dataset, public domain)); the steps come from our maths engine and the answer was checked independently. Download MP4 (0.2 MB) · Captions (WebVTT)

Steps on screen

1. The problem
Working with percentages
Percentage change from 50 to 40
2. Step by step
1. $40 - 50 = -10$
  Subtract the original value from the new value
2. $\frac{-10}{|50|} = -0.2$
  Divide the change by the absolute value of the original
3. $-0.2 \times 100 = -20\%$
  Multiply by 100
3. The answer
$-20\%$
(40 − 50) ÷ |50| × 100 = -20%
4. Check
- Check: 50 + -20% of |50| = 40

Transcript

The problem. Here is the problem: Percentage change from 50 to 40. Measure how much a value changed relative to its original value.

Step by step. Subtract the original value from the new value. Divide the change by the absolute value of the original. Multiply by 100.

The answer. So the answer is negative 20 percent (decrease). The value decreased by 20 percent.

Check. Check: 50 plus negative 20 percent of |50| equals 40.

About percentages

Percent of a number, what percent one number is of another, the whole from a part, and percent change.

Percent change from 50 to 40: Animated Step-by-Step Lesson