A part filled 10 frame is a visual representation of a number less than 10. It consists of a rectangular grid with 10 squares, arranged in two rows of five squares each. Each square represents one unit. When some of the squares are filled, it shows the number of units that have been counted or added. For example, if four squares are filled, it represents the number 4. The part filled 10 frame is a useful tool for teaching young children basic math concepts such as counting, addition, and subtraction. It helps them visualize numbers and understand the relationship between numbers and quantities.