4.NBT.5
Multiply a whole number of up to four digits by a one-digit whole number, and multiply two two-digit numbers, using strategies based on place value and the properties of operations. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models.
Explanation: We are multiplying 2-digit numbers by 2-digit numbers like this:
25 X 25
as well as multiplying up to 4-digit numbers by 1-digit numbers, like this:
4356 X 2 and 657 X 2
We teach several ways to solve these problems, and they are listed below with videos:
Area Model Multiplication 2-Digit X 2-Digit 4.NBT.5 [–This is helpful for solving in your head!]
Lattice Method 2-Digit X 2-Digit 4.NBT.5
Traditional Algorithm for Multiplying 2-Digit X 2-Digit 4.NBT.5
Multiplying 4 Digit by 1 Digit 4.NBT.5 (See alternate method below)
Multiply 4 Digit by 1 Digit Using Expanded Form – 4.NBT.5