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- Common Core MathK - 8High School

# Grade 1: Number and Operations in Base Ten

343 questions17 skills

# Grade 1: Number and Operations in Base Ten

343 questions17 skills

## 1.NBT.A.1

15 questions1 skill

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.

## 1.NBT.B.2

77 questions3 skills

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

25 questions1 skill

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

## 1.NBT.B.2b

25 questions1 skill

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

27 questions1 skill

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).

## 1.NBT.B.3

42 questions2 skills

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

## 1.NBT.C.4

209 questions11 skills

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.

Subtract within 100 using place value blocks

Add within 100 using place value blocks

Add within 100 using a number line

Add 1 or 10

Add 1s or 10s (no regrouping)

Select strategies for adding within 100

Break apart 2-digit addition problems

Subtract within 100 using a number line

Subtract 1-digit numbers with regrouping

Add 2-digit numbers by making tens

Regroup when adding 1-digit numbers

## 1.NBT.C.5

20 questions1 skill

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

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.

Skills for this standard are coming soon.