In this lesson, students begin understanding ten as a unit: "a ten". They rename their Rekenrek bracelet, the ten-frame, the fingers on two hands, and two 5-groups as 1 ten. They connect teen numbers to the unit form (for example, 1 ten and 1 one, 1 ten and 2 ones) and represent the numbers with Hide Zero cards. And they use their very own Magic Counting Sticks (i.e., their fingers) to help them compose 1 ten. By bundling 1 ten, students realize that, in the case of teen numbers, some ones are left over, which clarifies the meaning of the ones unit.