The Some Went Away Formula
The Some Went Away formula in Grade 4 math models subtraction word problems: Some − Some Went Away = What Is Left. For example, if LuAnn had 65 beads and used 13, the equation is 65 − 13 = 52 beads left. Covered in Chapter 3 of Saxon Math Intermediate 4, this formula helps students identify the three quantities in any subtraction story—the starting amount, the amount removed, and the remainder—and write the correct equation to solve for any missing piece.
Key Concepts
Property Some − Some went away = What is left.
Examples LuAnn had 65 beads and used 13, so she has $65 13 = 52$ beads left. Celia had 42 shells and 29 are left, so she sent $42 29 = 13$ shells away.
Explanation This is your formula for any 'disappearing act' problem! It connects your starting amount, what went away, and what's left. Use it to find any missing piece by plugging in the two numbers you already know. It's your secret weapon for solving subtraction word problems.
Common Questions
What is the Some Went Away formula?
Some − Some Went Away = What Is Left. It models any situation where a quantity is reduced: starting amount minus the amount removed equals the remaining amount.
How do you use this formula to write a subtraction equation?
Identify the starting amount (Some), the amount that left (Some Went Away), and what remains. Write the equation: starting − removed = remaining, then solve for the unknown.
How do you find the starting amount if you know what went away and what is left?
Rearrange the formula: Some = What Is Left + Some Went Away. For example, if 29 shells remain and 13 went away, the starting amount was 29 + 13 = 42.
When do Grade 4 students learn the Some Went Away formula?
This formula is introduced in Chapter 3 of Saxon Math Intermediate 4 as a structured approach to subtraction word problems.
What kinds of word problems use the Some Went Away formula?
Any story where items are used, spent, eaten, given away, or removed: spending money from a wallet, eating cookies from a jar, or fish leaving a pond.
How does the Some Went Away formula connect to algebra?
The formula represents a subtraction equation with a variable. Solving for an unknown piece uses inverse operations, which is the foundation of algebraic equation-solving.