The worksheet titled "Ordering Numbers Up to 20: A Fill-in-the-Blank Activity" is filled with sets of three numbers drawn on engaging pictures like birdhouses, bugs, and flowers. The numbers are always in order, but one number in the sequence is missing. Students use the number line at the top of the page to help them fill in the missing number. For example, one flowerpot contains the number 4, the next one is blank, and the third one contains the number 6. Students must fill in the number 5 on the blank pot.

The first section of each worksheet focuses on the numbers 0-9. The second section of the worksheet focuses on the numbers 0-20, giving students plenty of opportunities to practice developing important number sense concepts.

Ordering numbers is a foundational number sense concept that students must understand before moving on to more complex math concepts, like addition and subtraction. Filling in the blanks on a number line is one of the best ways to give students practice understanding numbers and how they relate to each other. For example, students could complete the missing numbers 2, 7, and 9 on a number line ranging from 0 to 10. As students get good at ordering small numbers, they can practice ordering large numbers up to 20 and then 100.