Multiplying with 10 MAFS.3.OA.3.7

Multiplying with 10 If you can skip count by 10, you can multiply with 10. There are 3 base ten rods. Each rod represents 10 ones. This can be represented by 3 groups of 10 or 3 × 10.

Let’s skip count by ten 3 times Multiplying with 10 If you can skip count by 10, you can multiply with 10. 10, 20, 30 There are 3 base ten rods. Each rod represents 10 ones. This can be represented by 3 groups of 10 or 3 × 10. Let’s skip count by ten 3 times to find what 3 tens is.

Let’s skip count by ten 3 times Multiplying with 10 If you can skip count by 10, you can multiply with 10. 10, 20, 30 There are 3 base ten rods. Each rod represents 10 ones. This can be represented by 3 groups of 10 or 3 × 10. Let’s skip count by ten 3 times to find what 3 tens is.

= 40 = 60 = 80 = 50 = 90 Multiplying with 10 4 groups of 10 (4 x 10) So, what is… 4 groups of 10 (4 x 10) 6 groups of 10 (6 x 10) 8 groups of 10 (8 x 10) 5 groups of 10 (5 x 10) 9 groups of 10 (9 x 10) = 40 = 60 = 80 Encourage students to skip count by tens to find the product. = 50 = 90

Multiplying with 10 Let’s look at our Multiplication Table…

Multiplying with 10 Find all the multiples of 10…

Multiplying with 10 What do you notice about the multiples of 10? All multiples of 10 have a 0 in the ones place. The order is skip counting by 10. The tens place increases by 1 each time.

Multiplying with 10 Let’s look at our 100 Chart…

Multiplying with 10 Find all the multiples of 10.

Multiplying with 10 What do you notice about the multiples of 10 on the hundred chart? The multiples of 10 are only in 1 column.

Keep It, Toss It What each pair of players needs: Keep It, Toss It Recording Sheet Spinner (and paperclip to spin the spinner) How to play: The younger player spins first. Spin the spinner and multiply the number by 10. Decide whether you want to keep the product or toss it. (You can only spin a TOTAL of 10 times. You can only keep 5 products.) Recording the product in the correct column. The older player repeats all the steps. Add 5 products to get your score. The player with the higher score wins. 50 20 80 10 60 30 90 80 360

What is one strategy you used for multiplying with 10? Closing What is one strategy you used for multiplying with 10? Skip count by 10 How do you know when to stop skip counting by 10? Draw it/Model it Add a zero to the other factor (5 x 10 = 50) Why does this work? Adding a zero is not a strategy that should be taught, but should be discovered by students. It works because when you multiply by a group of 10, you are adding a place (like in place value) to the factor.

Bonus Questions When you multiply 1-9 by ten, why are the products always two-digit numbers? Why do the products always have a 0 in the ones place? Products always have a 0 in the ones place because when you multiply by ten you do not have any ones. Visualize your base ten blocks. If you have 3 base ten blocks (which is 3 groups of tens) there are no ones that are modeled—there are only tens.

Exit Ticket Ms. Gomez has 6 shelves of books. Each shelf has 10 books. How many books does Ms. Gomez have on all her shelves? Model the problem. Write an equation that corresponds to it. Write another equation that corresponds to it. Write the answer to the problem in a complete sentence.