In 1st grade, children focus most on solving more difficult addition and subtraction problems and extend their understanding of place value (ones and tens).

##### Reading and Writing Larger Numbers

Read and write numbers from 20 through 120.

##### Counting Forward

Count forward between 1 and 120, starting at any number.

Understand addition as “putting together” and “adding to.” Understand subtraction as “taking apart” and “taking away from.” Understand comparing situations. Solve all of these situations with any of the three quantities as the unknown number.

##### Multiples of Ten

Quickly and accurately add numbers that total 10 or less, and subtract from numbers up to 10.

##### The Relationship

Understand the relationship of addition and subtraction. ##### Ways of Adding or Subtracting

Using objects and drawings, solve numeral and word problems that involve adding or subtracting numbers through 20. Use strategies like the ones shown in the example problem. ##### Understanding the Equal Sign

Understand the equal sign ( = ) means “is the same as.” Determine if addition and subtraction statements are true or false.

Which of the following statements are true? ##### Working With Equations

Work with addition and subtraction equations – math sentences that use numbers and symbols – to solve problems such as
8 + ? = 11 or 5 = ? – 3.

##### Understanding Place Value

Understand place value in one- and two-digit numbers. Understand that in two-digit numbers such as 79, the digit on the left is 7 tens and the digit on the right is 9 ones.

##### Understanding Category of Tens

Understand 10 as ten ones (1+1+1+1+1+1+1+1+1+1) or one ten. Understand 20 as twenty ones, or two tens, 30 as thirty ones, or three tens, etc. Understand numbers 11 to 19 as a ten and some ones.

##### Using Number Words

Say two-digit numbers using number words (79 is “seventy nine”).

Use “tens” and “ones” to explain the meaning of a two-digit number (“79 is seven tens, and nine ones).

##### Comparing Two-Digit Numbers

Compare two-digit numbers using the symbols > (greater than, or more than), = (equal to), and < (less or less than).

##### Single Digits and Multiples of 10

Mentally add 10 and subtract 10 from any two-digit number and explain the thinking used. Add a one-digit number (1 through 9) to any two-digit number, and add any two-digit number to any other two-digit number, within 100. Add 10 and subtract 10 from any two-digit number up to 100. Use concrete models or drawings to show the place values and explain the thinking involved.

##### Measuring Object Length

Measure the lengths of objects using a shorter object as a unit of measurement.

##### Ordering Objects by Length

Put objects in order by length, longest to shortest, and shortest to longest. Use correct terms to compare length: short, shorter, shortest; long, longer, longest.

##### Organizing Objects Into Categories

Organize objects into as many as three categories (by shape, color, size, etc.). Ask and answer questions about the number of objects in different categories. Represent the quantities of objects in as many as three categories, using drawings or charts.

##### Describing Shapes

Describe what defines shapes (number of sides; corners, or angles) and what does not (color, size). Build and draw shapes based on descriptions of their characteristics (properties).

Use toothpicks to make a shape with three sides.

Draw a shape that has four sides of the same length.

##### Divide Circles and Rectangles

Divide circles and rectangles into two equal pieces (called halves) and four equal pieces (called quarters).