Library›Addition Fluency›One card

A LITTLE SOMETHING WORTH KNOWING

A small discovery. Yours to pass on.

Math & LogicOne small ahaSum

6 + 21

Think it. Then flip it. ahamoraTap to reveal Back to the cue
Math & LogicOne small aha
Your new aha27

6 + 21 = 27. Changing the order gives 21 + 6, 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. 1796 + 22RECALL
    28

    Mental addition

    Open this card ↗
  2. 1806 + 23RECALL
    29

    Mental addition

    Open this card ↗
  3. 1817 + 13RECALL
    20

    Mental addition

    Open this card ↗