Library›Addition Fluency›One card

A LITTLE SOMETHING WORTH KNOWING

A small discovery. Yours to pass on.

Math & LogicOne small ahaSum

15 + 20

Think it. Then flip it. ahamoraTap to reveal Back to the cue
Math & LogicOne small aha
Your new aha35

15 + 20 = 35. Changing the order gives 20 + 15, 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. 35215 + 21RECALL
    36

    Mental addition

    Open this card ↗
  2. 35315 + 22RECALL
    37

    Mental addition

    Open this card ↗
  3. 35415 + 23RECALL
    38

    Mental addition

    Open this card ↗