Balance subtraction equations - up to three digits

Learning Objectives Define and identify key terms related to algebraic equations, such as 'variable' and 'equation'. Explain the concept of balancing an equation using inverse operations. Solve one-step subtraction equations with a variable using addition as the inverse operation. Accurately perform addition and subtraction with three-digit numbers to solve equations. Check their solutions by substituting the found value back into the original equation. Solve subtraction equations where the variable is the minuend or the subtrahend. Imagine you have a perfectly balanced seesaw ⚖️. What happens if you add weight to one side? To keep it balanced, what must you do to the other side? In this lesson, we'll learn how to keep mathematical equations balance...

TermDefinitionExample EquationA mathematical statement that shows two expressions are equal. It always has an equals sign (=).10 - 3 = 7 or x - 5 = 12 BalanceIn an equation, 'balance' means that both sides of the equals sign have the same value. If you change one side, you must change the other side in the same way to keep it balanced.If 5 = 5, then 5 + 2 = 5 + 2 (both sides become 7) VariableA letter (like x, y, or z) that represents an unknown number in an equation. Our goal is often to find the value of the variable.In the equation x - 20 = 50, 'x' is the variable. Inverse OperationsOperations that 'undo' each other. Addition is the inverse of subtraction, and subtraction is the inverse of addition.To undo subtracting 10, you add 10. (10 - 10 = 0, 10 + 10...

The Balancing Rule of Equations Whatever operation you perform on one side of an equation, you must perform the exact same operation on the other side to maintain equality. This rule ensures the equation remains true. If you add a number to the left side, you must add the same number to the right side. If you subtract, multiply, or divide, you do the same. Inverse Operation for Subtraction To isolate a variable that is being subtracted from, use addition. If $x - a = b$, then $x - a + a = b + a$, which simplifies to $x = b + a$. This rule helps you 'undo' the subtraction that is happening to the variable, moving the constant term to the other side of the equation and solving for the variable. Solving for a Subtrahend Variable If the variable is the subtrahend...