# 2.1: Number Towers

**At Grade**Created by: CK-12

What do you notice in the number tower below? What if you wanted to move the numbers in the cloud to the number tower so that the numbers were in order? In this concept, we will practice using deductive reasoning to fill in missing numbers.

### Guidance

When looking at a number tower and cloud like the ones above, we can fill in the number tower by moving numbers from the cloud to the tower. We want the numbers in order so the least number is on the top and the greatest number is on the bottom. We can start at the top and find the smallest number and put it at the top of the number tower under the 3. Continue until we have filled in the whole number tower.

#### Example A

Use the numbers in the clouds. Fill in cubes with numbers. The least number is on the top and the greatest is on the bottom.

**Solution:**

#### Example B

Use the numbers in the clouds. Fill in cubes with numbers. The least number is on the top and the greatest is on the bottom.

**Solution:**

#### Example C

Use the numbers in the clouds. Fill in cubes with numbers. The least number is on the top and the greatest is on the bottom.

**Solution:**

#### Concept Problem Revisited

If we fill in the cubes with numbers so that the least number is on the top and the greatest is on the bottom, this is the solution:

### Vocabulary

The ** least number** is the smallest number. The

**is the biggest number. In the set of numbers {1, 6, 3, 9, 7}, 1 is the least number and 9 is the greatest number.**

*greatest number*### Guided Practice

1.

2.

3.

**Answers:**

### Practice

### Image Attributions

Students fill in missing numbers on number towers so that numbers are ordered from least to greatest.