Addition and subtraction within 100

This course is a part of Early math, a 8-course Topic series from Khan Academy.

Learn to add and subtract two-digit numbers within 100.

This course contains 11 segments:

Adding 1s and 10s

Learn how to solve addition problems like 23+4 and 23+40.

Subtracting 1s and 10s

Learn how to solve addition problems like 24-3 and 45-30.

Intro to addition with 2-digit numbers

Learn how to add two-digit numbers. By the end of this tutorial, you'll be able to solve problems like 48+6 and 48+21. More advanced problems like 48+28 will be covered in a future tutorial.

Intro to subtraction with 2-digit numbers

Learn how to subtract two-digit numbers. By the end of this tutorial, you'll be able to solve problems like 48-9 and 48-31. More advanced problems like 48-29 will be covered in a future tutorial.

Strategies for adding and subtracting within 100

Learn strategies for adding and subtracting two-digit numbers.

Addition within 100

Learn to add two-digit numbers like 37 and 49.

Subtraction within 100

Learn to subtract two-digit numbers like 47 and 39.

Word problems within 100

Learn how to solve addition and subtraction word problems. Numbers used 100 or less.

Word problems with "more" and "fewer" (within 100)

Learn how to solve word problems that use the words "more" and "fewer". Numbers used are 100 or less.

Skip-counting

Learn to count by fives, tens, and hundreds.

Addition and subtraction missing value problems

Learn how to solve problems like "___ - 37 = 48" where you don't know one of the values in an addition or subtraction equation.