Think about the numbers seven and nine. Sophia showed the number seven in a ten frame. How can she show the number nine?
This row of the ten frame has five counters. And this row has two. Sophia made seven by adding five counters and two more. How could Sofia show nine? We know Sophia’s ten frame shows seven. So we can add more counters until we have nine altogether.
We’re starting with seven. If we add one more, there will be eight. And if we add two more counters, there will be nine altogether. Sophia can show the number nine by adding five counters and four more.
Five counters and four more makes the number nine.