Lengths

To compare two objects, we can check which is longer or shorter.
Lay them side by side and carefully line up one end on the same line. The object that goes further is longer. The other is shorter.
If we stand them up, the one that is higher is taller. The other is shorter.

The girl is taller than the boy.
The boy is shorter than the girl.

To measure how long an object is, we can use smaller items like paper clips, blocks, or erasers.
Use the same kind of item for the whole measurement. Line them up in a straight line right next to the object. Make sure there are no gaps between them. Then, count how many you used.

The cucumber is 4 erasers long.