10000 x 10000 = 100000000
10000 times 10000 is 100000000, one hundred million. Four zeros in each number and eight in the answer. Any pair of round numbers whose zeros add up to eight lands on the same total.
10,000 × 10,000 = 100,000,000
Adding 10,000 to itself 10,000 times gives the same answer.
Count the zeros, then add them
Each 10000 carries four zeros and a leading 1. Multiply two numbers of that shape and the zeros simply add: four plus four is eight, so the answer is a 1 followed by eight zeros. Written as powers of ten it is ten to the fourth times ten to the fourth, which is ten to the eighth. This is also 10000 squared.
Reading 100000000 out loud
One hundred million. Grouped in threes it is 100,000,000. Indian English calls it ten crore. Chinese and Japanese count in ten-thousands rather than thousands, so 10000 is one single unit there (wan, or man) and 100000000 is the next named unit up (yi, or oku) — in those languages this calculation is one unit multiplied by itself, which is exactly why the unit exists.
Nine digits breaks a pocket calculator
100000000 needs nine digits. A basic eight-digit pocket calculator cannot show it and will fall back to an error message or to scientific notation. That is the plain reason this sum gets typed into a search box instead of a keypad.
Other ways to share out eight zeros
Any pair whose zeros total eight gives the same answer, so 100000 x 1000 = 100000000 as well, and so does 10000000 x 10. Do not confuse the product with the sum: 10000 plus 10000 is only 20000.
| Calculation | Answer |
|---|---|
| 10000 x 100 | 1000000 |
| 10000 x 1000 | 10000000 |
| 10000 x 10000 | 100000000 |
Both smaller steps have pages: 10000 x 100 = 1000000 and 10000 x 1000 = 10000000. Index on multiplication answers.