Bringing Understanding to Dynamic Subtraction

Many students struggle to understand and remember the standard dynamic subtraction algorithm. Above is a great alternative to the standard algorithm. An alternative that brings understanding to what is being done when subtracting one number from another number. And it is easy to introduce. First play around with have and owe. Check out Crewton Ramone’s House of Math intro to negative numbers and integer toss game videos to see how to do this. From there you can quickly and easily introduce dynamic subtraction as shown above to even the littlest of kids. Start with smaller numbers first and then go bigger – after all bigger is funner! Don’t forget to use your blocks with all of this – keep it fun. After only a couple of examples you will find most children will be able to do dynamic subtraction with understanding.

Note: The minuend is the have and the subtrahend is the owe.

Thus: 15-8 would be have 15 owe 8 which can be further broken down to have 10 owe 0 and have 5 owe 8. 23-17 would be have 23 owe 17 which again can be further broken down to have 20 owe 10 and have 3 owe 7.

Also: With this method it doesn’t matter which place value you subtract first.

Update: 2nd Annual Convention and Trade Show in Maple Ridge

A big thank you to everyone who came out and visited our two tables at the 2nd Annual Convention and Trade Show in Maple Ridge back in June. It was busy and super fun. Next time though we will have someone come out just to take pictures for us. We were so busy talking with parents and playing math with the kids that we were only able to snap a few pictures over the course of our time there. The few pictures we did get we made into this short video for you all to enjoy.

EZ Math Set for sale on eBay – SOLD!

Mortensen Math EZ Math
EZ Math blocks and workbooks

SOLD! final bid – $10.50 USD. What a great deal! I am hoping it went to someone following this post. 

If you are looking for an alternative to the Mortensen More Than Math blocks there is a full set of EZ Math blocks for sale on eBay. It includes the blocks, workbooks, supplements, place value cards, and algebra cards. EZ Math blocks are no longer being produced due to copyright infringements so you can only find their sets used. EZ Math was derived from Mortensen More Than Math so it is a good alternative if you can’t afford the real deal. The full sets don’t come up often, especially at this price, so if you want one don’t procrastinate – go buy it!

Level 1 Chemistry

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Mortensen More Than Math really is more than Math!

Why did Jerry Mortensen include chemistry in the Mortensen More Than Math program? I can only speculate as to what his answer would have been but I believe that he would have stated that Mortensen More Than Math is a concept based math program so we can use the concepts of science, in this case chemistry, to introduce and teach math concepts. After all science is the application of math. Mathematical calculations are needed to explore important concepts in chemistry and bring understanding to them. And then I believe he would have asked “Why would we not use chemistry concepts to introduce and teach math concepts? and why wouldn’t we do so at an early age?” With this rationale it makes sense then that he would have included chemistry as part of a concept based math program such as Mortensen More Than Math.

There are 10 books of Chemistry.
They are like the other books – about 20 pages each.
They begin by introducing the concept of matter.
Level 1 Chemistry Books 1-2 Sample Pages

Door and draw prizes!

Marti Mortensen owner of Mortensen More Than Math generously donated a single Combo Kit worth $95 USD as a door prize and two Level 1 Algebra DVDs both worth $42 USD and two Skip Count CDs both worth $15.75 USD as draw prizes at the 2nd Annual Convention and Trade Show in Maple Ridge. The cost of shipping was donated by Anna’s Math Page. Come on out join the fun and maybe you will be one of the lucky winners who gets to take one of these items home with you!

Mortensen More Than Math Door and Draw Prizes!


The following is a message from Marti Mortensen the owner of Mortensen More Than Math,

“All the books and publications are available now and can be shipped to you right away.  Donna and I have been going over backorders and we believe that we have cleared them all up – but if we have overlooked any – we need customers to inform us.  Please write to us and give us a list of what you are waiting for.  We think we know but it would be very helpful if you could write to us and inform us of what you are still waiting for. We can ship them right away – we just need the information. If you are still owed anything please write to us at:

M o r t e n s e n M a t h @ i C l o u d . c o m

Thank you,
Marti Mortensen

Note: Please do not include the spaces in the above email address when emailing us. It is shown here with spaces to prevent
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