Exploring 2-Digit Addition Strategies

The video tutorial explains how to simplify addition problems by breaking them into tens and ones. It uses examples of adding 39 + 61 and 41 + 57, demonstrating how to decompose numbers into tens and ones for easier mental calculation. The tutorial emphasizes understanding place value and verifying equivalent expressions.

Why is it useful to break up addition problems?

• It helps in learning subtraction.

• It makes the numbers smaller.

• It helps in understanding multiplication.

• It can make the addition easier to compute.

Tags

CCSS.2.OA.A.1

In the first example, what does the '30' in the choice 30 + 60 + 90 + 10 represent?

• Three thousands

• Three hundreds

• Three tens

• Three ones

Tags

CCSS.2.NBT.A.3

Why is the choice 30 + 60 + 90 + 10 incorrect for 39 + 61?

• It includes a 30 which is not present in the original numbers.

• It includes a 10 which is not present in the original numbers.

• It includes a 60 which is not present in the original numbers.

• It includes a 90 which is not present in the original numbers.

Tags

CCSS.1.NBT.C.5

What is the correct breakdown of 39 + 61?

• 30 + 60 + 9 + 1

• 30 + 6 + 9 + 1

• 3 + 6 + 9 + 1

• 30 + 60 + 90 + 10

Tags

CCSS.2.NBT.B.5

What is the sum of 30 + 60?

• 60

• 90

• 100

• 30

Tags

CCSS.2.NBT.B.5

What is the sum of 9 + 1?

• 8

• 9

• 10

• 11

Tags

CCSS.1.OA.C.6

CCSS.2.OA.B.2

In the second example, what does the '4' in 41 represent?

• Four thousands

• Four ones

• Four tens

• Four hundreds

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CCSS.4.NBT.A.1

What is the correct breakdown of 41 + 57?

• 4 ones + 1 one + 5 tens + 7 tens

• 4 ones + 1 ten + 5 ones + 7 tens

• 4 tens + 1 ten + 5 ones + 7 ones

• 4 tens + 1 one + 5 tens + 7 ones

Tags

CCSS.2.NBT.B.6

Why is the choice with 'one ten' incorrect for 41 + 57?

• It incorrectly converts the one in the ones place to a ten.

• It incorrectly converts the four in the tens place to a one.

• It incorrectly converts the seven in the ones place to a ten.

• It incorrectly converts the five in the tens place to a one.

Tags

CCSS.1.NBT.C.4

CCSS.2.NBT.B.5

Why is the choice with 'four ones' incorrect for 41 + 57?

• It incorrectly converts the one in the ones place to tens.

• It incorrectly converts the seven in the ones place to tens.

• It incorrectly converts the five in the tens place to ones.

• It incorrectly converts the four in the tens place to ones.

Tags

CCSS.1.NBT.C.4

CCSS.2.NBT.B.5