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Anti Dots are....

  • The number that you are taking away from the larger number.
  • James Tanton invented them in a sandbox. The piles are positive numbers(dots) and the holes are negative numbers(anti dots)

How to SUBTRACT using exploding dots!

Links and Websites!

http://gdaymath.com/courses/exploding-dots/

www.theglobalmathproject.org

1) Draw dots and anti-dots

2) Do annihilation (draw lines from anti-dot to regular dot)

Practice Problems:

1) 6-5=__________

2)19-11=__________

3) 24-5=__________

bonus Challenge!!!

157,401-77,192=________

History Behind Exploding Dots:

Continued...

Subtraction:

Continued...

on the abacus, If you need to make calculation, for example, 8 plus 7 will be 15. Then you need to calculate it by breaking down 1 bead in the column of tens and 5 beads in the column of ones. The main idea of the abacus is that tens contains ones, and the hundreds contain tens and so on.

James Tanton teaching exploding dots

3) Explode the dot from higher place value to lower place value if there's an anti-dot left.

4) Write the number of dots left (you can never have anti-dots left, so don't worry about it) and put them under the box.

History Behind Exploding Dots!

Over 4,000 years ago, Exploding Dots might have been related to the way that Ancient Egyptians did math. They called it the Abacus. It was slightly different but was alike in many ways.

Practice problem answers

1) 6-5= 1

2)19-11= 8

3) 24-5= 18

bonus Challenge!!!

157,401-77,192= 80,209

Practice problem answers:

1) 276 divided by 12= 23

2) 325 divided by 3= 108 r 1

3) 3,954 divided by 24= 164

How to DIVIDE using exploding dots!

bonus challenge!!!

88,495 divided by 13 equals 6,807 r 18

Practice Problems:

1) Draw what the divisor would look like in dots in boxes.

2) Draw dividend in dots and boxes.

3) See the divisor's pattern in the dividend boxes.

1) 276 divided by 12= ______

2) 325 divided by 3=_______

3) 3,954 divided by 24=______

bonus challenge!!!

88,495 divided by 13

Dividing continued...

4) Put tally on top of the box that has the ones place for the divisor each time you see the pattern.

5) Add up tallies for each place value.

6) the remaining dots are the remainder

Exploding Dots: History and how to do it!

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