20 times 20 is 400 — with the shortcut, the division facts and a drill to make it stick
20 × 20 = 400. That is the short answer, and it is the same answer whichever way round you write the two numbers. Below is where 400 comes from, the shortcut that gets you there without counting, the division facts that travel with it, and the fastest way to move it from "I can work it out" to "I just know it".
20 × 20 = 400. Said out loud in the way most classrooms say it: Twenty twenties are four hundred.
Multiplying is repeated addition, so 20 × 20 is twenty twenties added together, or equally twenty twenties added together. Both routes land on 400.
Written the other way round the answer does not change. 20 × 20 = 400 as well, because multiplication is commutative — the order of the two factors never affects the product. That halves how many facts you actually have to learn: get 20 × 20 and you have 20 × 20 for free.
Twenty is double ten. Double 20 to get 40, then write a zero on the end: 400.
20 × 20 is a square number: 400 is what you get when 20 is multiplied by itself, which is why the square root of 400 is 20.
Because one of the factors is even, the answer has to be even. 400 is, so the parity check passes.
Every multiplication fact comes with a division fact on its back. These four all say the same thing about 20, 20 and 400: 20 × 20 = 400; 20 × 20 = 400; 400 ÷ 20 = 20; 400 ÷ 20 = 20.
Learning them as one family rather than four separate things is the single biggest shortcut in times-table practice. If you can answer "400 divided by 20" as fast as you can answer "20 times 20", the fact is genuinely learned rather than just recognised.
In the 20 times table, 400 is the twentieth step: 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400.
In the 20 times table it is the twentieth step instead: 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400.
Seeing the same number arrive from two directions is what makes it stick. 400 is a landmark in both rows, so whichever table you are drilling you meet it again.
20 × 19 = 380, 20 × 21 = 420, 19 × 20 = 380, 21 × 20 = 420. Those are the answers people most often give by accident when they are a beat too quick.
The gap between neighbours is worth knowing on its own: each extra twenty adds 20 to the running total, and each extra twenty adds 20. So if 20 × 20 = 400 is solid, you can reach 20 × 21 by adding 20 rather than starting again.
Recognising a fact and recalling it under time pressure are different skills. A fact you can work out in four seconds still costs you four seconds every time it appears inside a longer calculation.
Short daily bursts beat long sessions: a 60-second drill every day will fix a table faster than one twenty-minute sitting a week. Mix the fact you are learning in among ones you already know so recall is being tested, not the order of a list.
20 times 20 is 400. In words, twenty twenties are four hundred.
20 times 20 is also 400. Swapping the two factors never changes the answer, so 20 × 20 and 20 × 20 both come to 400.
400 ÷ 20 = 20, because 20 × 20 = 400. The matching fact is 400 ÷ 20 = 20.
Twenty is double ten. Double 20 to get 40, then write a zero on the end: 400.
Yes. 400 is the twentieth number in the 20 times table, and the twentieth number in the 20 times table.
Every multiplication fact from 2 × 2 to 20 × 20 has its own page here, and the full grid is on the multiplication chart.