Numbers · GameSpark Tutorials

Numbers are the most common values in a game — a score, an x position, a countdown. They can be whole (7) or have decimals (3.5), and you do maths on them with a handful of symbols.

1. The arithmetic operators

+ add — 2 + 3 is 5.
- subtract — 10 - 4 is 6.
multiply — 5 3 is 15.
/ divide — 12 / 4 is 3.
% remainder (modulo) — 7 % 3 is 1, what is left over after dividing.

See them run:

function draw() {
  cls(1);
  print('2 + 3 = ' + (2 + 3), 8, 8, 7);
  print('5 * 3 = ' + (5 * 3), 8, 20, 7);
  print('12 / 4 = ' + (12 / 4), 8, 32, 7);
  print('7 % 3 = ' + (7 % 3), 8, 44, 7);
}

💡

Wrap the maths in parentheses inside a print, like above. The + between the label and the parentheses joins text, while the + inside the parentheses adds. Without the parentheses the number would be glued on as text instead of added.

2. Build on a variable

Mix numbers with variables to compute things. % is especially handy for wrapping a value back to 0 — here a counter that cycles 0, 1, 2, 3, 0, 1, …:

let tick = 0;

function update() {
  tick = tick + 1;
}

function draw() {
  cls(1);
  print('tick: ' + tick, 8, 8, 7);
  print('cycles 0-3: ' + (tick % 4), 8, 20, 11);
}

3. Handy number helpers

GameSpark gives you helpers for common number jobs:

flr(3.7) rounds down to 3 (floor).
rnd(5) gives a random number from 0 up to (not including) 5.
abs(-4) is 4 — the distance from zero.
min(a, b) / max(a, b) pick the smaller / larger.

function draw() {
  cls(1);
  print('flr(3.7) = ' + flr(3.7), 8, 8, 7);
  print('abs(-4) = ' + abs(-4), 8, 20, 7);
  print('max(2, 9) = ' + max(2, 9), 8, 32, 7);
}

🎯

Try it: show 10 - score. Roll a dice with flr(rnd(6)) + 1 (1–6). Move a dot that wraps around with x = (x + 1) % 128.

What you learned

Numbers can be whole or decimal; do maths with + - * / %.
% is the remainder — great for cycling a value back to 0.
Parenthesise maths inside print so + adds instead of joining text.
Helpers like flr, rnd, abs, min, max cover common number jobs.