# Number & Operations in Base Ten

Number & Operationsin Base Ten (NBT)

Extend the counting sequence.

CCSS.MATH.CONTENT.1.NBT.A.1

Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.

Understand place value.

CCSS.MATH.CONTENT.1.NBT.B.2

Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:

CCSS.MATH.CONTENT.1.NBT.B.2.A

10 can be thought of as a bundle of ten ones — called a "ten."

CCSS.MATH.CONTENT.1.NBT.B.2.B

The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones.

CCSS.MATH.CONTENT.1.NBT.B.2.C

The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).

CCSS.MATH.CONTENT.1.NBT.B.3

Compare two two-digit numbers based on meanings of the tens and ones digits, recording the results of comparisons with the symbols >, =, and <.

Use place value understanding and properties of operations to add and subtract.

CCSS.MATH.CONTENT.1.NBT.C.4

Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.

CCSS.MATH.CONTENT.1.NBT.C.5

Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

CCSS.MATH.CONTENT.1.NBT.C.6

Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero differences), using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.

Number & Operations in Base Ten (NBT) 1.NBT.1

1.NBT.A.1

Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.

Watch This Video

Missing numbers between 0 and 120 | Counting | Early Math | Khan Academy

## Khan Academy: Practice finding missing numbers in a list of numbers between 0 and 120.

Do these activities: KHAN ACADEMY 1.NBT.A.1 ACTIVITIES

Number & Operations in Base Ten (NBT) 1.NBT.A1

IXL Activities

Number & Operations in Base Ten (NBT) 1.NBT.2

1.NBT.B.2

Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:

1.NBT.B.2a

10 can be thought of as a bundle of ten ones called a "ten."

1.NBT.B.2b

The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones.

1.NBT.B.2c

The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).

Watch This Video

Introduction to place value | Place value (tens and hundreds) | Early Math | Khan Academy

1.NBT.B.2

## Khan Academy: Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:

Do these activities: KHAN ACADEMY 1.NBT.B.2 - ACTIVITY 1 - Groups of ten objects

Watch This Video

Two-digit place value challenge

Do these activities: KHAN ACADEMY 1.NBT.B.2 - ACTIVITY 2 - Two-digit place value challenge

1.NBT.B.2a

## Khan Academy: Practice grouping objects by tens.

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Introduction to place value | Place value (tens and hundreds) | Early Math | Khan Academy

Number & Operations in Base Ten (NBT)

1.NBT.B2a

IXL Activities

1.NBT.B.2b

## Khan Academy: The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones.

Number & Operations in Base Ten (NBT)

1.NBT.B2b

IXL Activities

1.NBT.B.2c

## Khan Academy: Practice grouping objects by tens.

Watch This Video

Introduction to place value | Place value (tens and hundreds) | Early Math | Khan Academy

Number & Operations in Base Ten (NBT)

1.NBT.B2c

IXL Activities

Number & Operations in Base Ten (NBT) 1.NBT.3

1.NBT.B.3

Compare two two-digit numbers based on meanings of the tens and ones digits, recording the results of comparisons with the symbols >, =, and <.

Watch This Video

Comparing whole numbers | Place value (tens and hundreds) | Early Math | Khan Academy

Number & Operations in Base Ten (NBT)

1.NBT.B3

IXL Activities

Number & Operations in Base Ten (NBT) 1.NBT.4

1.NBT.C.4

Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.

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Comparing adding 1 and 10

Number & Operations in Base Ten (NBT)

1.NBT.C4

IXL Activities

Number & Operations in Base Ten (NBT) 1.NBT.5

1.NBT.C.5

Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

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Adding 1 vs. adding 10 | Addition and subtraction | 1st grade | Khan Academy

Number & Operations in Base Ten (NBT) 2.NBT.2

2.NBT.A.2

Count forward and backward within 1000; skip count by 5's, 10's, and 100's beginning at any multiple of 5.

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Skip-counting by 5s

Number & Operations in Base Ten (NBT) 2.NBT.A2

IXL Activities

Number & Operations in Base Ten (NBT) 2.NBT.4

2.NBT.A.4

Compare two three-digit numbers based on meanings of the hundreds, tens, and ones digits, using >, =, and < symbols to record the results of comparisons.

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Comparing whole numbers | Place value (tens and hundreds)

Number & Operations in Base Ten (NBT)

2.NBT.A4

IXL Activities

Number & Operations in Base Ten (NBT) 2.NBT.8

2.NBT.B.8

Mentally add or subtract 10 or 100 from any given number between 100 and 900.

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Skills for this standard are coming soon to Khan Academy.

Do these activities: KHAN ACADEMY 2.NBT.B.8 ACTIVITIES - Coming Soon

Number & Operations in Base Ten (NBT)

Extend the counting sequence, understand place value, and apply place value understanding.

Counting Games

Jumping Chicks

Power your chicks by counting lily pads.

Koala Karts

Power your racecar by counting discs.

Challenging Games

Canoe Puppies Race Game

Add two-digit numbers correctly to win the race.

Missing Number Addition

Choose a target sum from (20-100) to practice.

Missing Number Subtraction

Choose a target difference from (20-100) to practice.