Balance subtraction equations - up to two digits

Learning Objectives Define a balanced equation and identify the variable. Explain the inverse relationship between addition and subtraction. Solve for an unknown minuend in a subtraction equation (e.g., n - 15 = 30). Solve for an unknown subtrahend in a subtraction equation (e.g., 50 - x = 20). Verify a solution by substituting the value back into the original equation. Write a simple subtraction equation with a variable to represent a real-world problem. Imagine a seesaw is perfectly level. What happens if one person jumps off? 🤔 Let's learn how to keep our math equations perfectly balanced, just like that seesaw! In this lesson, you will become an equation detective, finding the missing numbers that make subtraction equations true. This important skill helps you sol...

TermDefinitionExample EquationA mathematical sentence stating that two expressions are equal. It always has an equals sign (=).45 - 15 = 30 is an equation. VariableA symbol, usually a letter like 'x' or 'n', that stands for an unknown number we need to find.In the equation 60 - n = 25, 'n' is the variable. Balanced EquationAn equation where the value on the left side of the equals sign is exactly the same as the value on the right side.The equation 50 - 10 = 40 is balanced because both sides have a value of 40. Inverse OperationsOperations that 'undo' each other. Addition is the inverse of subtraction.To undo subtracting 12, you can add 12. MinuendThe number you are subtracting from. It is the first number in a subtraction problem.In 85 - 20 = 65, t...

The Missing Minuend Rule If $x - a = b$, then $x = a + b$ Use this rule when the first number (the minuend) is the missing variable. To find it, add the other two numbers together. The Missing Subtrahend Rule If $a - x = b$, then $x = a - b$ Use this rule when the number being subtracted (the subtrahend) is the missing variable. To find it, subtract the difference from the first number.