Work through subtraction facts one card at a time. Each flash card shows a subtraction problem; tap to flip it and reveal the answer, then use Next to carry on. The whole deck runs on screen, so it is ready on a phone in the car or on a laptop at the kitchen table.
Every deck is dealt at random from the subtraction facts, and answers never go below zero. Use the practice settings to choose how big the numbers get, or to switch the deck to a different operation.
A card shows a subtraction problem. Tap it to flip it over and see the answer, tap again to flip back, and use Previous and Next to move through the twenty cards in the deck.
No. The deck only draws problems where the first number is at least as large as the second, so every answer is zero or more.
Yes. The flash cards are free to use with no account and no sign-up, at home or in the classroom.