The point C is on the number line at -1 and the point E is at 3. We count the number of units from C to 0, which is 1 and from 0 to E, which is 3. We add the sum, 3 + 1 = 4.
Another way to show it is 3 - (-1) = 3 + 1 = 4.
Thus CE = 4
We repeat the process for BD. -4 -(0) = -4 - 0 = -4. However, distances are positive so we report its opposite, 4.
Thus BD = 4
Therefore CE = 4 and BD = 4
