Multiplication Answers

Eighty-nine calculations, one page each, all of them sums people type into a search box instead of a calculator. Every page prints the answer as text, shows the working, and seeds the calculator with that pair.

12 × 12 = 144

First number Second number

Adding 12 to itself 12 times gives the same answer.

Every page in this section

The ones looked up most

Calculation	Answer	What makes it worth a page
100 x 100	10000	A square number, and one hectare in square metres
20 x 100	2000	Constantly confused with 20 percent of 100
100 x 10	1000	The kilo in kilogram, kilometre and kilowatt
1000 x 1000	1000000	One million, and one megapixel
100 x 15	1500	Ten times, then half again
30 x 100	3000	The same two-place shift on a round thirty
100 x 12	1200	Months in a century, and the dozen shortcut
50 x 100	5000	Half of 100 x 100, so half of 10000

Three families, one rule each

Most of the list is a whole number against a power of ten. Multiplying by 100 shifts the digits two places left, by 1000 three places, by 10000 four places. Written as powers, the exponents simply add: 100 is ten squared and 1000 is ten cubed, so 100 x 1000 lands on ten to the fifth, 100000. That is the entire method for perhaps sixty of these pages, which is why each one carries something beyond it.

Where counting zeros breaks

The zero trick is a habit, not a rule, and decimals expose it. 0.07 x 1000 is 70. 0.5 x 100 is 50. 0.003 x 10000 is 30. Nothing gains a zero in any of those; the decimal point moves instead, and the answer can come out smaller than the number you started with. Think of every one of these as a shift and the decimals stop being a special case.

Calendar and clock numbers

Some of the busiest pages are here because of what the product counts, not because the sum is hard. 100 x 365 is 36500, a century of days before you put the leap days back. 100 x 52 is 5200 weeks. 86400 x 1000 is 86400000, which is how many milliseconds a day holds, since a day holds 86400 seconds.

The other half of the site

Repetition is multiplication applied to text rather than to a quantity. The repeater takes a phrase and prints it 100, 1000 or 10000 times, and the arithmetic follows you there: a ten-character line at 100 copies is 1000 characters plus the line breaks.