An unknown is a missing number in an equation. It is often shown with a letter or a blank space. Your job is to figure out what number makes the equation true.
The unknown is like a puzzle piece. When you find the correct number, both sides of the equation match.
To solve an addition equation with an unknown, think about what number must be added to reach the total.
You can subtract the known number from the total to find the missing number.
To solve a subtraction equation with an unknown, decide whether the unknown is the number being subtracted or the starting number.
If the unknown is at the beginning, add to find it. If the unknown is being subtracted, subtract to find it.
To solve a multiplication equation with an unknown, think about what number multiplied by the known number gives the product.
You can divide the product by the known number to find the unknown.
To solve a division equation with an unknown, decide whether the unknown is the number being divided or the divisor.
Use multiplication to help check your answer. If the multiplication works, the solution is correct.
Inverse operations are pairs of operations that undo each other. Addition and subtraction are inverses, and multiplication and division are inverses.
Using inverse operations helps you check your work and understand how equations are connected.
After solving an equation, replace the unknown with your answer to see if both sides are equal.
If both sides match, your answer is correct. If not, solve again using a different strategy.