Red

The top row is full plus 3 boxes on the bottom row.
What is 8?

One row is full.
What is 5?

The top row is full plus 2 boxes on the bottom row have dots.
What is 7?

10 and 3 more
What is 13?

The 10 frame is full
What is 10?

10 and 5 more
What is 15?

10 and 9 more
What is 19?

10 and 7 more
What is 17?

10 and 2 more
What is 12?

10 and 1 more
What is 11?

10 and 4 more
What is 14?

10 and 8 more
What is 18?

10 and 6 more
What is 16?

Two ten frames are filled up
What is 20?

The 10 frame is full, except for 1 box
What is 9?