Extend the counting sequence | Students count past 100 and read and write numbers all the way to 120, picking up where they left off in kindergarten. | 1.NBT.A |
Count to 120, starting at any number less than 120 | Students count, read, and write numbers up to 120, starting from any number, not just 1. They also look at a group of objects and write the number that shows how many. | 1.NBT.1 |
| | Students learn that the position of a digit tells you its value. A 2 in the tens spot means twenty, not two. | 1.NBT.B |
Understand that the two digits of a two-digit number represent amounts of tens… | A two-digit number like 47 means 4 tens and 7 ones, not just a string of digits. Students learn to see any number from 10 to 99 as a mix of tens and ones. | 1.NBT.2 |
10 can be thought of as a bundle of ten ones — called a "ten." | Ten single objects grouped together make one "ten." This idea is the foundation of how our number system works, and students use it to understand numbers like 20, 30, and beyond. | 1.NBT.2.a |
The numbers from 11 to 19 are composed of a ten and one, two, three, four… | Numbers from 11 to 19 are made of one group of ten plus some leftover ones. Thirteen, for example, is one ten and three ones. This is the foundation of how our number system works. | 1.NBT.2.b |
The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four… | Counting by tens means 30 is three groups of ten, 50 is five groups of ten, and so on. Students learn that each decade number (10, 20, 30...) tells you exactly how many tens are inside it. | 1.NBT.2.c |
Compare two two-digit numbers based on meanings of the tens and ones digits… | Students look at two numbers (like 47 and 63), figure out which has more tens, and write whether one number is greater than, less than, or equal to the other using the symbols >, <, and =. | 1.NBT.3 |
Use place value understanding and properties of operations to add and subtract | Adding and subtracting with tens and ones. Students learn that the position of a digit changes its value, then use that idea to add and subtract two-digit numbers. | 1.NBT.C |
Add within 100, including adding a two-digit number and a one-digit number | Students add numbers up to 100 by keeping the tens and ones separate. They use drawings or objects to show their thinking, and learn that sometimes ten ones need to be grouped into a new ten. | 1.NBT.4 |
Given a two-digit number, mentally find 10 more or 10 less than the number… | Students pick a two-digit number and figure out, in their head, what it looks like with ten added or ten taken away. No counting needed. They also put that thinking into words. | 1.NBT.5 |
Subtract multiples of 10 in the range 10–90 from multiples of 10 in the range… | Students subtract tens from tens, like 70 minus 40, using blocks or drawings to show their thinking. They connect what they drew to a written number sentence and explain how they got the answer. | 1.NBT.6 |