Students explore the concept of modular arithmetic and cryptography. In this modular arithmetic and cryptography lesson, students use applets to explore modular arithmetic using a clock and Caesar Ciphers. Students exchange their ciphers...

Students solve multiplication word problems by using base 10 blocks and drawing pictures. In this multiplication lesson plan, students also write a reflection of their work.

In this exercise, students practice breaking apart two-digit addition problems. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.

Practice adding two-digit numbers by making tens on Khan Academy. If you are stuck, watch a refresher video or choose to get a hint. Test yourself to see how many you can get correct!

An activity to practice addition. Materials needed include cuisenaire rods (or Base 10 blocks) and numeral cards (0-9).

Practice breaking apart problems like 23+45 into problems like 20+40+3+5. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Practice your double-digit addition on this site.

A website that gives practice problems for double-digit addition.

In this exercise, students practice subtracting two-digit numbers (no regrouping). Students receive immediate feedback and have the opportunity to watch a tutorial video, get hints, and try questions repeatedly.

[Free Registration/Login may be required to access all resource tools.] The video is a 2 part word problem using addition and subtraction of 2-digit numbers. The video is followed by practice problems to assess student understanding of...

Practice breaking apart big addition problems using place value. For example, 234+567 is the same as 200+500+30+60+4+7. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive...

In this exercise, students practice adding two-digit numbers by making tens. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.

In this exercise, students practice adding two-digit numbers by making tens. Students receive immediate feedback and have the opportunity to watch tutorial videos, get hints, and try questions repeatedly.

In this exercise, students practice adding two-digit numbers (no regrouping). Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.

[Free Registration/Login may be required to access all resource tools.] The video shows how to add three, two-digit numbers. The video is followed by practice problems covering the topics in the video.

[Free Registration/Login may be required to access all resource tools.] The video describes how to solve a two-digit addition word problem. The video is followed by a series of practice questions to assess student comprehension of the...

[Free Registration/Login may be required to access all resource tools.] The video describes how to solve a 2-digit addition problem without regrouping. The video is followed by practice problems.

[Free Registration/Login may be required to access all resource tools.] The video describes how to solve a 2-digit addition problem without regrouping. The video is followed by practice problems.

In this exercise, students practice comparing three-digit numbers. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.

In this exercise, students practice regrouping with two-digit number minus one-digit number. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.

Practice solving problems like 24 + 45. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Learn how to solve two-digit addition problems, and then practice the skill with interactive problems.

[Free Registration/Login may be required to access all resource tools.] The video shows how to add 3, two-digit numbers followed by additional practice problems.

[Free Registration/Login may be required to access all resource tools.] The video models how to add two-digit numbers using regrouping. The video is followed by practice problems.