LibraryAddition FluencyOne card

A LITTLE SOMETHING WORTH KNOWING

A small discovery. Yours to pass on.

Math & LogicOne small ahaSum

2 + 17

Think it. Then flip it.
ahamoraTap to reveal
Back to the cue
Math & LogicOne small aha
Your new aha19

2 + 17 = 19. Changing the order gives 17 + 2, the same sum. Source: Addition

ahamoraReference ↗

Keep the thread going

One answer is a beginning.

Share a little curiosity, or follow it into the full collection.

Flip the full deck →

More from Addition Fluency

A few more worth knowing.

  1. 613 + 7RECALL
    10

    Mental addition

    Open this card ↗
  2. 623 + 8RECALL
    11

    Mental addition

    Open this card ↗
  3. 633 + 9RECALL
    12

    Mental addition

    Open this card ↗