A complete unit with direct instruction to the student, ample practice problems and word problems. Common Core aligned. Great for independent practice/homework.
Multi-Digit Multiplication covers multi-digit multiplication and some related topics. The focus is on multi-digit multiplication (also called algorithm of multiplication, or multiplying in columns).
We start out by multiplying by whole tens and hundreds (such as 20 × 4 or 500 × 6). After this is mastered, we study a very important concept of multiplying in parts (also called partial products
algorithm). It means that 4 × 63 is done in two parts: 4 × 60 and 4 × 3, and the results are added.
This principle underlies all other multiplication algorithms, so it is important to master. We do not want students to learn the multiplication algorithm “blindly”, without understanding what is going on with it.
Multiplying in parts is also tied in with an area model, which, again, is very important to understand.
Before showing the traditional form of multiplication, the lesson Multiply in Columns—the Easy Way shows a simplified form of the same, which is essentially just multiplying in parts. You may skip that
lesson at your discretion or skim through it quickly if your child is ready to understand the standard form of the algorithm, which is taught next.
Students also study estimation and multiplying with money. Many kinds of word problems abound in all of the lessons. Students are supposed to practice writing a number sentence for the word problems—essentially writing down the calculating they are doing.
After that, we multiply two-digit numbers by two-digit numbers. Again, we first study partial products and tie that in with an area model. The lesson Multiplying in Parts: Another Way is optional. After that,
the standard algorithm for multiplying a two-digit number by a two-digit number is taught, and the unit ends.
I hope you find this book helpful with your math teaching!