Look at the lines below and write down the correct answer.

AB = cm;

CD = cm;

AB + CD = cm.

AB = 3 cm.

The starting point of line CD is 4 and the end point is 9. 9 cm – 4 cm = 5 cm. So the length is 5 cm.

The total length AB + CD = 3 cm + 5 cm = 8 cm.