infinitum

overview

pick a mode and solve the puzzle. play untimed, timed, or zen. a run tracks score and level. three wrong answers in a row reset the round to level 1.

decathlon is a separate option that cycles through every mode. it is timed only; free play is 1 to 15 minutes.

arithmetic

• factora, find all factors of the target number.
• target, build an equation that equals the target. each round offers a random subset of operators.
• summism, add digits, with plus signs, until you reach the target.
• make x, build an equation that makes x from the cards you are dealt. you must use the cards.
• make x², solve for x in the given equation.
• percent, quick percent questions: a percent of a number, what percent, discounts, and raises.

number properties

• primal, decide whether the number is prime (p) or composite (c).
• modulo, find the remainder after dividing evenly. for example, 10 divided by 3 leaves 1.
• divis, name numbers that divide the target evenly.
• complement, fill in the blank: what do you add to hit the total?
• binary beats, convert binary to decimal.

estimation

these modes reward a close, fast answer. exact counting is not required unless hardcore or sudden death is on.

• quantize, estimate the number of dots without counting them all. the eye icon replays the dots, up to twice per problem. learn mode uses plain one-color dots.
• fermi questions, estimate to the nearest power of ten.
• probable, guess the real odds: 1 in how many?
• rate, guess a real-world percentage from 0 to 100. exact is a hit; within 10% counts as close (exact only in hardcore or sudden death).
• portion, guess how full a shape is (bar, grid, pie, and others). within 5% counts as close (exact only in hardcore or sudden death).

modifiers

• progressive, every few solves, the round gets harder.
• hardcore, one miss resets your score. estimation modes also require an exact answer.
• sudden death, misses cost time; hits add it back. estimation modes require an exact answer.
• learn, smaller numbers everywhere. quantize uses plain one-color dots. percent sticks to easy 10 / 25 / 50 values.

next

next is a mode in the same picker as the others. you get five numbers and choose what comes sixth, from the options on screen.

a run is a clock: zen, or 1, 3, or 5 minutes. one point for each sequence you solve. difficulty follows your streak: easy at the start, harder as you keep getting them right. the rule is shown after you answer.

skip deals a new sequence. one you had looked at and not answered counts as a miss. the light bulb crosses out one wrong answer, once per sequence. your best is kept for each timer.