Library›Addition Fluency›One card

A LITTLE SOMETHING WORTH KNOWING

A small discovery. Yours to pass on.

Math & LogicOne small ahaSum

13 + 28

Think it. Then flip it. ahamoraTap to reveal Back to the cue
Math & LogicOne small aha
Your new aha41

13 + 28 = 41. Changing the order gives 28 + 13, 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. 38413 + 29RECALL
    42

    Mental addition

    Open this card ↗
  2. 38513 + 30RECALL
    43

    Mental addition

    Open this card ↗
  3. 38614 + 26RECALL
    40

    Mental addition

    Open this card ↗