Subtracting with Symbols

The video tutorial explains how to solve subtraction problems with unknowns using letters, often X, to represent these unknowns. It introduces various strategies, such as using a hundreds chart and rearranging equations, to find the value of the unknown. The tutorial demonstrates how to handle different positions of unknowns in subtraction sentences and compares methods to find the most effective strategy for solving these equations.

What is the purpose of using a letter like X in a subtraction problem?

• To represent an unknown number

• To represent a known number

• To make the problem more complex

• To simplify the problem

If you start at 13 on a hundreds chart and count back 5, what number do you land on?

• 10

• 7

• 9

• 8

In the problem 14 - X = 8, how many numbers do you count back from 14 to find X?

• 5

• 6

• 7

• 4

How can you rearrange the equation 15 - X = 10 to find X?

• 15 - 10 = X

• X - 15 = 10

• 10 - 15 = X

• X = 15 + 10

In the equation 12 - X = 3, what is the value of X?

• 8

• 7

• 9

• 6