Math Mammoth Add & Subtract 4 worktext covers mental addition and subtraction strategies; adding and subtracting in columns; Roman numerals; the connection between addition and subtraction, missing addend problems, and solving word problems with bar diagrams; order of operations; bar graphs, line graphs, and money problems.
The first lessons cover the "technical aspects" of adding and subtracting, such as mental math strategies, terminology, and adding in columns.
Then the student solves word problems with the help of bar diagrams. Next, we solve simple missing addend equations using subtraction, such as x + 20 = 60. We use bar diagrams to illustrate these and connect them with fact families. We also practice subtracting in columns and borrowing.
The answers are appended. The book is suitable for 3rd or 4th grade.