Hey there! Ready to be a math detective? Today we will learn how to find missing numbers using simple balance tricks!
In pre-algebra, we use letters like 'x' to stand for a missing number. We call this letter a variable because its value can change depending on the puzzle.
An equation is like a balanced playground scale. To keep both sides perfectly equal, whatever math you do to one side, you must also do to the other side.
To solve for 'x', we must get it all by itself. We do this by using opposite operations, like using subtraction to undo addition.
✏️ Worked example
Solve for the missing number: x + 5 = 12
Identify the goal: We want to get the variable 'x' by itself on the left side of the equals sign.
Look at the operation: Currently, 5 is being added to 'x'.
Do the opposite: The opposite of adding 5 is subtracting 5.
Keep it balanced: Subtract 5 from both sides of the equation.
Calculate the left side: (x + 5) - 5 leaves us with just 'x'.
Calculate the right side: 12 - 5 equals 7.
Write your final answer: x = 7.
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