Big 4
One number, four quick questions. A five-minute mental maths warm-up in 28 levels.
How Big 4 works
Each level gives you one number and four quick questions about it, such as double it, round it to the nearest 10 or list its factors. Work out all four in your head, then click a box to check the answer.
There are 28 levels, from odd and even numbers up to prime factorisation. Click New Number for a fresh one, or print any level as a worksheet with answers.
Three ways to use it
On the board
Go full screen with F. Space reveals every answer, 1 to 4 reveal one at a time, N gives a new number and the arrow keys change level, so a clicker can run the whole thing.
On paper
Worksheet prints the same number four times on a page. Worksheet (mixed) gives four different numbers, so each table can work on its own one. The answers are on page 2.
Step up a level
Start a level below where you expect, and reveal one box at a time. Once all four answers have been seen, a Next level button appears.
Choose a level
Each card shows the numbers you get and the four questions.