This engaging activity focuses on the importance of place value when thinking about or building numbers. Simply pass out all of the ones and tens cards to your students, then verbally give a number. If students have a card that will contribute to making the given number, they come forward to the front of the room. Create an addition sentence using the expanded form of the number, then have the students put the cards together to reveal the number. Did they make the correct number? If so, continue on with another number and have a great time building number sense!