Lesson 2: Multiply two-digit multiples of 10 by two-digit numbers using the area model.

Property

To represent the multiplication of a multiple of 10 by a two-digit number, decompose the two-digit number into its tens and ones. The multiple of 10 becomes one dimension of an area model, and the decomposed tens and ones become the parts of the other dimension.

Examples

Property

To multiply multiples of 10, multiply the non-zero digits and then adjust the place value based on the units being multiplied.

• Tens $\times$ Tens = Hundreds: $(a \times 10) \times (b \times 10) = (a \times b) \times 100$
• Tens $\times$ Ones = Tens: $(a \times 10) \times c = (a \times c) \times 10$

Examples

Property

To find the total product, add the partial products together.

Examples