Interactive unit fractions
With this interactive tool, you can visualize and explore unit fractions in comparison to a unit square (one whole). Children (or the teacher) can drag unit fraction pieces (1/2, 1/3, 1/4, 1/5, 1/6, 1/8, 1/9, 1,10, 1/12, 1,16, and 1/20) onto a square that represents one whole. You can see that, for example, 6 pieces of 1/6 fit into one whole, or that 3 pieces of 1/9 are equal to 1/3, or many other similar relationships.
Ask students, for example, to fill the unit square using some 1/5, some 1/20, and some 1/10 pieces, and write an addition sentence to match what they did.
Or ask them to find what kind of pieces, and how many of them, fill the 1/3 piece. They can once again write an addition sentence from their work, such as 1/9 + 1/9 + 1/9 = 1/3.