You burn time on cleanup
The problem turns into a fight with signs, factoring, and cancellation before you even reach the real math.
If algebra cleanup keeps hijacking your study sessions, this is the kind of lesson that helps fast: one rule, one example, one clean practice rep, and a very clear reason it matters.
A lot of Math GRE frustration is not “advanced math.” It is losing control of algebra in the middle of a bigger problem. When that happens, you waste time, lose confidence, and miss the real idea the question is testing.
The problem turns into a fight with signs, factoring, and cancellation before you even reach the real math.
One bad simplification step can quietly poison the rest of the solution.
Limits, derivatives, and graph questions feel random when the algebra under them is shaky.
You can cancel shared factors. You cannot cancel terms inside a sum.
Excluded values come from the original denominator, even after you simplify.
Factoring usually exposes the real structure faster than pushing symbols around blindly.
Simplify (x² - 9) / (x² - 3x) and keep every excluded value visible.
Step 1
Factor both parts first: (x - 3)(x + 3) / x(x - 3).
Step 2
Before canceling anything, mark the original restrictions: x ≠ 0 and x ≠ 3.
Step 3
Now cancel the shared factor and keep the restrictions next to the result: (x + 3) / x, x ≠ 0, 3.
Simplify (x² - 16) / (x² - 4x).
Start the same way: factor both parts, find the original excluded values, then cancel only the shared factor.
Factor to (x - 4)(x + 4) / x(x - 4). The original denominator excludes x = 0 and x = 4. After canceling (x - 4), the result is (x + 4) / x, x ≠ 0, 4.
The lesson tells you the rule clearly instead of making you dig for it.
The example shows the trap directly, then gives you one clean rep to lock it in.
When the foundations are steadier, later calculus and mixed review stop feeling so chaotic.