Three little challenges, every day.Pick your level. Use every number.
Tap a number, an operator, then another number.
Make exactly 10 using all four digits, each once. Tap two numbers and +, −, × or ÷, then combine them. The result becomes a new tile you can use again.
Numbers can be used in any order. Fractions and negative results are allowed. No joining digits or dividing by zero.
For 5, 9, 6, 5:5 × 5 = 259 + 6 = 1525 − 15 = 10
Choose Easy, Moderate or Hard. Each has its own daily puzzle and saved progress. Play one or all three; everyone gets the same puzzles for the Sydney date.
Two ways to scoreEfficiency rewards simpler arithmetic. Complexity rewards more involved arithmetic. Both are out of 100 and compare your solution with all valid solutions to that puzzle. They are separate goals, not added together. Your daily score adds your best Efficiency scores from Easy, Moderate and Hard, for a maximum of 300. Uncompleted puzzles contribute zero. Your Complexity total is shown separately.
Each + or − costs 1; × costs 2; ÷ costs 3. Each fractional result adds 4, negative result adds 2, and result with absolute value above 20 adds 1. The simplest solution earns 100 Efficiency; the most complex earns 100 Complexity. Scores scale down to 10 at the other extreme. If all solutions have equal cost, both scores are 100.
Easy puzzles have a minimum cost of 3; Moderate 4–5; Hard 6 or more. These are arithmetic-based difficulty estimates. Hints are labelled, with no score penalty. Undo and restarting do not add points. Your best scores are saved on this device.
A little challenge for your friends. Your calculations stay a secret.