Rules

• Only digits 1–9, and each digit at most once per equation.
• × is calculated before + and −: 2 + 3 × 4 is 14, not 20.
• Any valid answer counts. There is no single "intended" answer.
• Correct answers move you up a level (more boxes, more ×), wrong ones move you down.

Keys

Type a digit to fill the highlighted box. ← → move between boxes, Backspace erases, Del clears all, Enter submits. Enter does nothing until every box is filled. Typing a digit that's already used moves it to the box you're on.

How to read a code

• Digit i of the code says which top symbol ends up in bottom position i.
• Official example: top ■ ▲ ✚ ● becomes ✚ ▲ ● ■, so the code is 3241 (3rd, 2nd, 4th, 1st).
• From level 4 two boxes are chained: the output of the first box is the input of the second, and one of the two codes is given.

Keys

1 2 3 pick a code. In practice, a wrong answer stops and shows where each symbol came from. Enter goes on.

The loop

1. A dot lights up in one of 16 holes.
2. You answer a yes/no puzzle (5 seconds).
3. Repeat 2 to 6 times, then click the holes where the dots were, in order.

Round 1 asks "Is it symmetrical?", round 2 "Rotated but identical?", round 3 "Is the equation correct?" (line patterns added or taken away).

Keys

Puzzles: Y or ← for yes, N or → for no. Recall: click the holes, Backspace undoes the last one, Enter submits once every position is placed.

What runs

Set up like the real thing

• Laptop, plugged in, Chrome or Firefox, full screen (F11).
• Quiet room, phone in another room.
• No stopping between steps except the short screen that introduces the next game.

The real games look different and their exact timing may vary. The skills are the same.

Three drills

• Mixed: products, sums, differences and order of operations. The daily warm-up.
• Reverse products: "42 = ? × ?". Type two different digits, like 6 then 7. This is the core Digit skill: seeing a target and knowing which products get you there.
• Order of operations: "3 + 4 × 2". Trains you to always do × first.