Library›Addition Fluency›One card

A LITTLE SOMETHING WORTH KNOWING

A small discovery. Yours to pass on.

Math & LogicOne small ahaSum

15 + 30

Think it. Then flip it. ahamoraTap to reveal Back to the cue
Math & LogicOne small aha
Your new aha45

15 + 30 = 45. Changing the order gives 30 + 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. 39716 + 24RECALL
    40

    Mental addition

    Open this card ↗
  2. 39816 + 25RECALL
    41

    Mental addition

    Open this card ↗
  3. 39916 + 26RECALL
    42

    Mental addition

    Open this card ↗