Divisibility Rules Poster Options

I am working on converting old anchor charts and notes to typed posters.

Divisibility Rules Poster Options:

Color:

Slide1

Black and White:

Slide2

Use these photos as a poster to display in your classroom, or print for use in student notebooks/binders.  Here is the FREE .pdf:  DivisibilityRulesPoster.

So, what is this trick for the 7’s divisibility rules?  

Check it out:

  • Double the last digit and subtract it from the remaining part of the number.  If the answer is either 0 or it is divisible by 7, then the original number is divisible by 7.

Example:

  • Start with the number:  1015.
  • Isolate the last digit:  1015 .
  1. Double the last digit.  5 x 2 = 10.
  2. Subtract the result (10) from the remaining part of the number (101):  101 – 10 = 91
  3. Determine whether your answer is equal to 0 or divisible by 7.  If it is, the number is divisible by 7.  If it is not, the number is not divisible by 7.
  • 91 divided by 7 equals 13, which is a whole number.
  • Since 91 is divisible by 7, that means 1015 is also divisible by 7.
  • If you are curious, and don’t feel like working it out… 1015 divided by 7 equals 145.

It is probably easier just to do long division in most cases, but it is always fun to learn a new trick 😉

Check out my post on making a divisibility rules foldable.

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