Find an unknown addend

In today's lesson, we will be finding an unknown addend when the sum is changed.

Video

Click on the play button to start the video. If your teacher asks you to pause the video and look at the worksheet you should:

  • Click "Close Video"
  • Click "Next" to view the activity

Your video will re-appear on the next page, and will stay paused in the right place.

Lesson summary: Find an unknown addend