S3: Subtraction using a number line Posted on March 26, 2017 by mrsgraham2013 Using a number line we can subtract within 30. It is important to clearly mark the starting and ending numbers. Make sure that when you jump that you move backwards only by one number at a time. We are subtracting 1 each time we jump backwards. Advertisements Share this:TwitterFacebookLike this:Like Loading... Related