10000 x 10 = 100000
10000 times 10 is 100000. Both numbers are powers of ten, so you can count zeros instead of multiplying: four from 10000 and one from 10 give five zeros, or one hundred thousand.
10,000 × 10 = 100,000
Adding 10,000 to itself 10 times gives the same answer.
Counting zeros instead of multiplying
10000 is ten to the fourth power and 10 is ten to the first. When both sides are powers of ten you add those exponents: 4 + 1 = 5. The answer is ten to the fifth, written 100000. No column arithmetic is needed at any point.
What 100000 is called
100000 is one hundred thousand. In the Indian numbering system the same quantity is one lakh and is grouped as 1,00,000 instead of 100,000. The digits and the value are identical; only the comma placement changes.
The zero that changes the name
Add one more zero to the second number and the answer changes name completely: 10000 x 100 = 1000000, one million. Miscounting by a single zero is the usual error here, so group the zeros in threes from the right and read off the group name.
Same answer, different pair
100 x 1000 also equals 100000, because the five zeros can be split between the two numbers any way you like. Take a zero back off and you get 1000 x 10 = 10000.