Adding Multiple Two-Digit Numbers with Friendly Strategies

This video tutorial teaches how to add up to four numbers using addition facts and friendly numbers. It covers the concept of doubles, friendly numbers, and the commutative property of addition. Through practical examples, such as calculating miles run, pounds lifted, and sit-ups done, the tutorial demonstrates how to rearrange numbers for easier addition. The lesson emphasizes that numbers can be added in any order to achieve the same sum.

What are 'doubles facts' in addition?

• Subtracting numbers from each other

• Numbers that are added to themselves

• Multiplying a number by two

• Adding two different numbers

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CCSS.2.OA.B.2

CCSS.1.OA.C.6

What does it mean if numbers are 'friendly' in addition?

• They are easy to add or subtract

• They are prime numbers

• They are multiples of five

• They are difficult to calculate

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CCSS.1.OA.A.1

How many miles were run on Tuesday?

• 6 miles

• 4 miles

• 8 miles

• 10 miles

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CCSS.3.OA.D.8

What is the total number of miles run in the week?

• 24 miles

• 30 miles

• 26 miles

• 28 miles

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CCSS.3.OA.D.8

What principle states that the order of numbers does not change the sum?

• Associative property

• Commutative property

• Distributive property

• Subtractive property

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CCSS.1.OA.B.3

How much weight was lifted on Wednesday?

• 6 pounds

• 11 pounds

• 7 pounds

• 9 pounds

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CCSS.3.OA.D.8

What is the total weight lifted over the days mentioned?

• 30 pounds

• 33 pounds

• 35 pounds

• 32 pounds

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CCSS.2.OA.A.1

How many sit-ups were done in the second set?

• 8 sit-ups

• 12 sit-ups

• 14 sit-ups

• 9 sit-ups

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CCSS.1.OA.A.1

What is the total number of sit-ups done?

• 45 sit-ups

• 43 sit-ups

• 42 sit-ups

• 40 sit-ups

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CCSS.1.NBT.A.1

How can friendly numbers be used to simplify addition?

• By rounding them up

• By multiplying them

• By adding and subtracting one

• By dividing them