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Math Mammoth Add & Subtract 2-B

Math Mammoth Add Subtract 2-B math book cover
95 pages
(includes answers)

Sample pages (PDF)
Contents & Introduction
Adding with Whole Tens
Going Over Ten
Two-Digit Numbers Ending in 9
Regrouping in Subtraction 1
Mental Subtraction Methods

Prices & ordering

PDF download USD $6.30

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Printed copy $10.75

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Math Mammoth Add & Subtract 2-B is a continuation to the book Math Mammoth Add & Subtract 2-A. The goal of this book is to study addition and subtraction within 0-100, both mentally and in columns, especially concentrating on regrouping in addition (carrying) and in subtraction (borrowing).

Mental math is important because it builds number sense. This book includes many lessons that practice mental math. For example, the child practices adding and subtracting two-digit numbers when one of the numbers is a whole ten (such as 30 + 14 or 66 − 20).

The students also learn to solve sums such as 36 + 8 or 45 + 9 with mental math (there is a regrouping), comparing them to the sums 6 + 8 and 5 + 9. Since 6 + 8 fills the first ten and is four more than the next ten, the sum 36 + 8 fills the next whole ten (40), and is four more than that, or 44.

At the same time, students also learn to add two-digit numbers with regrouping. This is explained in detail with the help of visual models (base-ten blocks). You are welcome to use actual physical manipulatives, if you prefer. The main concept to understand is that 10 ones are regrouped to form a new ten, and this new ten is written using a little “1” in the tens column.

After addition, the lessons focus on column subtraction, initially without regrouping and then with regrouping.

The lesson Regrouping practices breaking down a ten into 10 ones. It is crucial that the child understands what happens here. Otherwise, they might end up only memorizing the procedure, and will probably at some point misremember how it was done. If you notice that the child does not understand the concept of regrouping, provide more practice with concrete manipulatives or visual exercises before proceeding.

After learning regrouping, students practice mental subtraction in two separate lessons. One of them expounds on several methods for mental subtracting. The other is about Euclid's game—a fun game that also practices subtraction of two-digit numbers.

You can find videos to match with the topics of this book at our 2nd grade math videos page, in the sections about 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.


Thank you SO much for the free download of Data & Graphs!! I had purchased several blue series books for my son but hadn't gotten that yet and it was exactly what I needed next.

I've been so impressed with your curriculum. My son is autistic and non-speaking and your curriculum has been accessible to him. He does not do well with manipulatives like some other curricula use because he seems to think in numbers like I do. My son is 6 and using Place Value 1 & 2, Add/Subtract 2A and 2B right now.

Great product! We'll continue buying once we finish up 2nd grade!

June 2018

Check out also these free addition & subtraction games and activities at our site: You might also be interested in the following books and resources:
  • Math Mammoth Add & Subtract 2-A — a worktext about "easy" additions and subtractions within 0-100, memorizing the basic addition facts of single-digit numbers, and word problems (grades 1-2).
  • Math Mammoth Add & Subtract 3 — a worktext about adding and subtracting 3-digit numbers with regrouping and with mental math, estimation, and word problems (grades 2-3).
  • Math Mammoth Place Value 2 — a worktext about three-digit numbers (place value), comparing, ordering, rounding, bar graphs, and pictographs (grade 2).
  • Math Mammoth Place Value 3 — a worktext about four-digit place value, adding & subtracting 4-digit numbers mentally, rounding, estimating, and order of operations (grade 3).
  • Math Mammoth Clock — a worktext about reading the clock, elapsed time, and calendar (grades 1-3).

Better Yet - Bundle Deals!

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All Inclusive Bundle - $275 (download)

"Everything" Bundle - $330 (download)

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*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.
  • K5 Learning offers download versions of the Blue series.
  • TPT sells the Light Blue Series downloads, plus topical units.
  • 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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