backsolvingAnswering a multiple-choice question by putting the answer choices into the problem, one at a time, until one makes every condition true.
You’ll leave with these skills
01Find the correct number choice by checking it in the original problemPut each number choice into the original equation or word problem and pick the one that fits every fact the problem gives.
02Tell when testing the choices is faster than solvingTest the choices when they are plain numbers and solving the equation would take several steps.
03Rule out several choices with one test of a middle choiceIf the result changes in one direction as the choices increase, a failed middle choice can rule out choices farther from the target on that side. Without that condition, test the remaining choices separately.
04Check a choice in Desmos by typing it as the unknown’s valueType the choice as the unknown’s value in one input box, such as a = 10, and the problem’s calculation in the next, then change the number to test another choice.
This lesson is part of the full library
207 lessons that teach every skill the SAT tests
71Math
40Reading
24Grammar
10 full-length practice tests to build test-day stamina and confidence
A Desmos simulator to solve math questions faster
A step-by-step guide to every practice test question
The Bluebook Simulator, so test day feels familiar
A drawing for every key term, so new ideas make sense at a glance
