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# Math Mammoth Add & Subtract 2-A

72 pages

## Prices & ordering

Printed copy \$9.60

Printed copy £4.56, full color
US shipping available

Este libro en español

Math Mammoth Add & Subtract 2-A deals with two main themes:

• strategies for adding and subtracting within 0-20; such as adding just one more, a trick with nine and eight, and subtracting using addition;
• memorizing the basic addition and subtraction facts of single-digit numbers with an answer between 10 and 18.

While focusing on addition and subtraction techniques, the lessons also include many word problems.

The goal is to memorize the facts, or at least become so fluent with them that an outsider cannot tell if the child remembers the answer or uses some mental math strategy to get the answer.

Some children will accomplish this quicker and need less practice, whereas others will take longer. Thus, don’t assign all the exercises in the book by default. Use your judgment, and try to match the amount of exercises to your child’s need. The ones that don’t get assigned can be used later for review. You can also use games to reinforce the facts, and in place of some of the exercises in the book (a list of games is provided in the book).

Learning addition and subtraction facts is quite important for later study. For example, regrouping in addition and subtraction (carrying/borrowing) requires the ability to recall the basic facts efficiently and fluently.

We will start the book with a few mental math strategies (Add Using “Just One More” and A Trick with Nine and Eight). The lesson Adding within 20 reviews those strategies and gives more practice. These initial lessons don't yet involve actual memorization techniques.

The lesson Subtract to Ten explains another basic strategy, and has to do with subtracting in parts. For example, to do 13 − 5, one can subtract 5 in two parts: first do 13 − 3, which equals 10, and then subtract the rest, or 2 more. Memorizing the subtraction facts will be more efficient, but I want children to understand this strategy, because it is useful in many other situations also.

Then we review how to complete the next whole ten, which is an important concept. An example of this concept is the question: What number do you add to 23 to get 30? As an equation, we write: 23 + __ = 30.

In the next lesson, we study sums that go over ten, doing these sums in two parts. For example, in the sum 9 + 7, the child first completes 10 by adding 9 + 1. Then, the child adds the rest, or 6, to 10. Learning this prepares the child for addition facts where the sum is more than 10.

The next lessons, Adding with 9, Adding with 8, Adding with 7, and Adding with 6, provide lots of practice for learning and memorizing the basic addition facts. There are 20 such facts:

9 + 2 till 9 + 9:   8 facts
8 + 3 till 8 + 8:   6 facts
7 + 4 till 7 + 7:   4 facts
6 + 5 till 6 + 6:   2 facts

The last part of the book includes various lessons titled Number Rainbows and Fact Families with.... These give lots of practice and reinforcement for the basic addition and subtraction facts, emphasizing the connection between addition and subtraction as a strategy for subtraction facts.

We also offer videos that match these particular lessons Choose the section for addition and subtraction facts.

The followup to this book, Add & Subtract 2-B, practices adding and subtracting two-digit numbers mentally and in columns (regrouping).

The PDF version of this book can be filled in on a computer, phone, or tablet, using the annotation tools found in many PDF apps. See more.

Check out also these free addition & subtraction games and activities at our site: You might also be interested in the following books and resources:

## Customer Testimonials

Just wanted to thank you for this [advice]. After reading your advice, we bought Add & Subtract 2A and have been working through it in tandem with her other math book. I think it's just what she needed - she is learning how to think through addition facts rather than just memorizing them....or not memorizing them, lol. The improvement is so encouraging :) Once we wrap up her level 2 book [in the other program], I am planning to make Math Mammoth our main math program!

Thanks,
Danielle

This image was sent to one by a customer. The girl in the picture loves rainbows and organizes a lot of her things by color, using Roy G Biv order. The picture is about her first "math rainbow" for learning addition & subtraction facts, which she was very excited about!
We bought the light blue add/subtract and place value books from 2A forward to go back and get what my concept talented but math facts never mastered dd needs to review.

Keep doing the great work you're doing. It's amazing to see my dd age 12, who was doing fine with pre-algebra, knows all mult/division facts from homeschool years, but just never got the addition and subtraction facts (when she went to school) gain confidence with the reviews without any grade-level stigma.

Thanks!

Kate
My son finally doesn't hate to do math. He is a little behind in math and this year with your workbooks he is well on his way back to grade level and with a great understading of how numbers work. Thanks Maria, for helping my son to learn and enjoy math!
Mabel
I have a 2nd grade daughter who just "didn't get" math. We've been using another well known math program which was just moving too fast for her. Fortunately, I had purchased Mammoth Math [Add & Subtract] 2A over the summer and it has turned her into an "I get it" kid! We just completed 2A and will be starting 2B shortly. It's been an awesome supplement and my daughter looks forward to her daily math worksheets!
I can't believe how much more confident she's become in her computation skills and she's even soaring with the story problems. Thanks Mammoth Math!
The following is one of the winning entries to Math Mammoth 2008 Thanksgiving Contest.

Well, it turned out to be just what Gracie needed! You teach math topics efficiently and interestingly, with no extraneous fussiness. After doing a few weeks of your math (slowly - 2 pages per day) Gracie asked to know a bit more about the writer. We went online so she could read your "about" page, and was so pleased to put a name and face to your math books. You see, she discovered that you like patterns, and believes you hide patterns all through your math worksheets. In fact, she now notices lots of math patterns quickly, and makes extra effort with her math worksheets to make sure Mrs. Miller doesn't "trick" her. Her ability to see patterns makes learning math facts so much easier. It never occurred to me (or my Engineer husband) to explain math the way you do. You seem to be speaking her "math language" and - finally - math makes sense to her.

Today, I'll be ordering the Blue A/S 2-B, so we can carry on with Gracie's math seamlessly. I'm so thankful you wrote this particular (Blue) series. I'm sure most homeschoolers order the Light Blue Full Curriculum, and I hope it's a good fit for them. But, there are students (perhaps with Special Needs, or just with Math Phobia) who just can't manage a full curriculum. I hope they'll consider the Blue series, which attacks math skills individually, in a way which builds skill-upon-skill, and teaches little patterns and tricks in a very do- able (and reasonably priced!) format.

Cheers,
Lauri Bolland (and Gracie)
Thank you so much for new edition of the Add/Subtract 2a book!! I gave the new pages as homework tonight and am amazed to see the excitement the rainbows have created working with inverse operations/fact families. Thank you, again! I love incorporating your worksheets into our lessons it has made my children confident independent workers! Your newsletters and blogs are so worth the read!! The information you have and receive about math is making a tremendous difference in my home everyday!! Your consideration, work, time, and effort is greatly appreciated by my family.

Shai Hawk

## Better Yet - Bundle Deals!

*BONUS*: Buy any bundle listed above, and get the fully upgraded Soft-Pak software for FREE (includes 4 math and 2 language arts programs, complete with on screen and printable options).

## How and where to order

You can buy Math Mammoth books at:

• Here at MathMammoth.com website — simply use the "Add to cart" buttons you see on the product pages.
• Rainbow Resource carries printed copies for the Light Blue series books, plus several CDs (Light Blue and Blue series).
• Homeschool Buyers Club offers download versions of the Light Blue series, plus the Blue series bundle.
• Homeschool Planet sells the digital versions of the main curriculum and lesson plans to go with them.
• Lulu sells printed copies for most of the Math Mammoth materials (various series).

By purchasing any of the books, permission IS granted for the teacher (or parent) to reproduce this material to be used with his/her students in a teaching situation; not for commercial resale. However, you are not permitted to share the material with another teacher.

In other words, you are permitted to make copies for the students/children you are teaching, but not for other teachers' usage.

Math Mammoth books are PDF files. I recommend you use Adobe Reader to view them, including if you use a Mac. You can try other PDF viewers, but they may at times either omit or mess up some of the images.
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