1. Think About Ten 3-2 Carlos Suzy x 1 2 3 4 5 6 7 8 9 10 12 14 16 18 201 2 3 4 5 6 7 8 9 10 12 14 16 18 20 15 21 24 27 30 28 32 36 40 25 35 45 50 42 48 54 60 49 56 63 70 64 72 80 81 90
100
Suzy
Carlos
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2. Multiplying by 10 10
X 6 10 20 30 40 50 60 60
Multiplying by 10 is like skip counting by 10s.
Connecting multiplying by ten to repeated addition or skip counting
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3. Multiplying by 10 1 x 10 = 10 6 x 10 = 60 10 x 2 = 20 10 x 7 = 7030
8 x 10 = 80
10 x 4 = 40
10 x 9 = 90
Do you see a pattern in the products?
10 x 10 =
100
5 x 10 = 50
What do you notice when multiplying by 10?
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4. Multiply 5 x 6 5 X 6 30 10 x 6 = 60 30 half of 60 is 30 5 60 5
Using relationship of 5 and 10 as a strategy
Multiplying by 5 is like multiplying by 10 and then taking HALF (because 5 is HALF of 10).
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5. The five facts are just half the tens facts.7
x 5
Multiply by
Take half of that -- 35 35
The five facts are just half the tens facts.
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6. Let’s try that strategy.
5 x 8 = 40
10 x 8= 80
1st multiply by 10
Half of 80 is 40
2nd divide in half
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7. 5 x 9 = 45 10 x 9= 90 Half of 90 is 45 Let’s try that again.
1st multiply by 10
Another example.
2nd Divide in half
Half of 90 is 45
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8. 5 10 9 5 Let’s play “Half of Tens” 5 x 5 is half of
10 x 5 or
half 50. It’s 25.
5 x 9 is half 90. That’s 45!
10 x 5 = 50
10 x 9 = 90
Demonstration of the game: Turn over a digit card. First player multiplies it by 10. Second player multiplies it by 5 (or halves the 10 fact that his/her partner just computed). For the next number card, Player 2 goes first.
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9. Warm Up Game: Half of Tens
Materials: A deck of number cards (0-10)
Object: Practice multiplying by tens and fives.
Rules:
Player 1 draws a number card and multiplies it by 10.
Player 2 multiplies the same number by 5 (half of the “x10” product).
Partners check for accuracy.
Allow time for students to play this game to develop fluency with fives using this strategy.
© 2014 Teacher to Teacher Publications, Inc.

10. 5 x 6 7 5 Let’s play “Product Crossing with Fives” 5 x 6 is 30.
0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50
5 x 5 is 25. So I cross off 25.
5 x 6 is 30.
5 x 7=…
10 x 7 is 70.
Half of 70 is 35.
So 5 x 7 = 35. I can cross off 35.
5 x 6 7 5
Demonstration of the game: Same as twos version.
0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50
© 2014 Teacher to Teacher Publications, Inc.

11. Warm Up Game: Product Crossing with Fives
Materials: A deck of 0-10 number cards
Object: Cross off each of the numbers on the list of products by multiplying correctly and quickly.
Rules: Each player makes a list of the products of 5 (0, 5, 10, … 50) and turns that list facedown. Place the first factor card, “5”, on the table.
Players take turns:
Drawing a card from the deck (the other factor).
Multiplying the number on the card by five.
If players say the product correctly and quickly, they
cross it off the list. Then turn list facedown again.
Reshuffle cards as needed. The first player to
cross off all the numbers wins.
Allow time for students to play this game to develop fluency with multiplying by 5.
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