This file includes two stations. They are aligned to Common Core Standard 4.NBT.3. They both relate to rounding. Either station could be used in third or fifth grade as well.
The first center is called "Find the Midpoint." I write the answer to all of my stations on the back of the card once I've cut it out. In this station, the students are given two numbers on a vertical number line. They must find the midpoint. There are 39 cards for this center.
The second center is called "Round that Number." Students pick a number card and a rounding card. Then they round the number card to the place indicated on the rounding card. There is no answer key for this because answers will vary based on the combinations of cards.