Solving Subtraction Equations Involving Decimals

The video tutorial explains how Barbara used a gift card to buy a sweater and how to determine the initial amount on the card. It introduces an equation to represent the situation and demonstrates solving it using inverse operations. The solution is verified by substituting back into the equation, confirming the initial amount was $19.01. The lesson concludes with a summary of solving one-step subtraction equations involving decimals.

Barbara used a gift card to buy a sweater for $15.20 and had $3.81 left. What equation represents the initial amount on the card?

• b + 15.20 = 3.81

• b - 3.81 = 15.20

• b + 3.81 = 15.20

• b - 15.20 = 3.81

What is the first step in solving the equation b - 15.20 = 3.81?

• Subtract 15.20 from both sides

• Divide both sides by 15.20

• Multiply both sides by 15.20

• Add 15.20 to both sides

After adding 15.20 to both sides of the equation, what is the resulting equation?

• b = 15.20

• b = 18.01

• b = 19.01

• b = 3.81

How can you verify the solution to the equation b - 15.20 = 3.81?

• By checking if b + 3.81 equals 15.20

• By checking if b - 15.20 equals 3.81

• By checking if b + 15.20 equals 3.81

• By checking if b - 3.81 equals 15.20

What was the initial amount on Barbara's gift card before the purchase?

• $15.20

• $3.81

• $18.01

• $19.01