Number Pyramid
each brick is the sum of the two below

Play Number Pyramid — Brick Maths Puzzle

00:00
Tap a brick, then typeTab jumps to the next empty brickGreen = checks out

How to play Number Pyramid

Number pyramids are a classroom favourite. Every brick holds the sum of the two bricks it rests on — so the top brick is built from the whole bottom row.

Work upwards by adding, or downwards by subtracting: if a brick is 15 and one of its supports is 6, the other is 9. Multiplication pyramids work the same way with times and divide.

Expert pyramids leave gaps that need algebra — call a missing brick ‘a’, write each brick in terms of it, and solve.

How to play Number Pyramid

Fill every brick so that each one equals the sum (or product) of the two bricks directly below it.

The rules

  1. Bricks are stacked so each one rests on two bricks below.
  2. In an addition pyramid, each brick equals the sum of the two below it.
  3. In a multiplication pyramid, each brick equals their product.
  4. Given bricks can’t be changed.

Playing here

  1. Choose add or multiply, how many rows and a difficulty, then press New Puzzle.
  2. Tap a brick and type its number on the pad (or keyboard). Tab or ↵ jumps to the next empty brick.
  3. With checking on, a brick turns green when it matches the two below it, red when it doesn’t.
  4. Hint shows the next brick to work out — and whether to add, subtract, multiply or divide.

Tips

The full guide, with a worked example and common mistakes: How to play Number Pyramid.

Questions

Which age is it for?

3-row addition pyramids suit ages 5–6; 5-row and multiplication pyramids suit 8–11; algebra pyramids suit 11+.

Can bricks be negative?

Not in generated puzzles; the solver accepts negative numbers.

Is there always one answer?

Yes — every puzzle here is checked to have exactly one solution.

How do I check a pyramid from a worksheet?

Open the Number Pyramid Solver, type the bricks you know and press Solve.

Related