Grid-in
A grid-in is a digital SAT Math question with no answer choices: the student types the answer into a box. College Board calls them student-produced response questions.
Also written as: student-produced response, SPR, free-response
Why it matters
They remove the safety net. There is nothing to eliminate, nothing to work backwards from, and no partial credit — which makes them the question type where a correct method still loses the point most often. They are also where entry-format errors live, and an entry error is invisible to ordinary checking because the work is right.
What people get wrong
Three specific rules catch people. Negative answers are allowed. Mixed numbers are not — they must be entered as improper fractions or decimals, because the box reads the fraction bar differently from how a student intends it. And the entry field has a character limit that silently stops accepting input rather than warning you, so long decimals need a decision about rounding made during the solve, not at the box.
Practise this on real adaptive questions
PrepGenix runs the same module-adaptive format as Bluebook, with scoring handled server-side. Free to start.