Library›Addition Fluency›One card

A LITTLE SOMETHING WORTH KNOWING

A small discovery. Yours to pass on.

Math & LogicOne small ahaSum

11 + 20

Think it. Then flip it. ahamoraTap to reveal Back to the cue
Math & LogicOne small aha
Your new aha31

11 + 20 = 31. Changing the order gives 20 + 11, 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. 30811 + 21RECALL
    32

    Mental addition

    Open this card ↗
  2. 30911 + 22RECALL
    33

    Mental addition

    Open this card ↗
  3. 31011 + 23RECALL
    34

    Mental addition

    Open this card ↗