How to find 10 percent of 40
"Percent" means per hundred, so 10% is the fraction 10/100, or 0.1 as a decimal. Taking 10 percent of 40 means multiplying 40 by that fraction:
10% of 40 = 40 x 10 / 100
= 400 / 100
= 4The same answer comes from the decimal form: 40 x 0.1 = 4. And because multiplication is commutative, 10% of 40 equals 40% of 10, which is sometimes the easier way to see it in your head.
Mental math shortcut
10% of 40 is 4 (move the decimal one place left), and 1% is 0.4. Build 10% from those pieces: 1 x 4 = 4.
Nearby percentages of 40
| Percent | Of 40 | 40 minus it | 40 plus it |
|---|---|---|---|
| 1% | 0.4 | 39.6 | 40.4 |
| 5% | 2 | 38 | 42 |
| 9% | 3.6 | 36.4 | 43.6 |
| 11% | 4.4 | 35.6 | 44.4 |
| 15% | 6 | 34 | 46 |
| 20% | 8 | 32 | 48 |
| 25% | 10 | 30 | 50 |
| 30% | 12 | 28 | 52 |
| 50% | 20 | 20 | 60 |
| 75% | 30 | 10 | 70 |
10 percent of other amounts
| Amount | 10% of it |
|---|---|
| 10 | 1 |
| 20 | 2 |
| 25 | 2.5 |
| 30 | 3 |
| 50 | 5 |
| 60 | 6 |
| 75 | 7.5 |
| 80 | 8 |
| 100 | 10 |
| 120 | 12 |
Where this comes up
A 10% discount on a 40 price takes off 4, leaving 36. A 10% tip or tax on 40 adds 4, for a total of 44. If 40 is a score out of a possible total, 10% of it is the share 4 represents. For percent change, reverse percentages, and "X is what percent of Y", use the full percentage calculator.