10000 x 20 = 200000
10000 times 20 is 200000. Count the zeros: four in 10000, one in 20, so the answer is a 2 followed by five zeros. The calculator below handles any other pair.
10,000 × 20 = 200,000
Adding 10,000 to itself 20 times gives the same answer.
The working
Multiply the leading digits first, then put the zeros back. 1 x 2 = 2. The 10000 brings four zeros and the 20 brings one, so five zeros follow the 2, giving 200000.
Said out loud that is two hundred thousand. That is 2 multiplied by 10 to the fifth power.
Why zero-counting is safe here
Both numbers are a small digit followed by zeros, so no carrying can happen. That is what makes this pair quicker in your head than on a keypad. If you prefer stepping, double 10000 to get 20000 and then add one zero for the remaining factor of ten.
Three routes to the same answer
200000 turns up more than once on this site, because the zeros can be shared out differently between the two numbers:
- 10000 x 20 = 200000
- 2000 x 100 = 200000
- 200 x 1000 = 200000
Each pair carries five zeros in total and a 2 out front, so all three land in the same place.
The slip to watch for
One stray zero multiplies the answer by ten. 10000 x 200 is 2000000, not 200000. Count the zeros in both numbers before you write the answer, not after.
Nearby: 10000 x 10 = 100000 and 1000 x 20 = 20000.