Grid-ins: the marks students lose for no reason
You solved it correctly and still got it wrong, because of how you typed it. This happens to good students, and it is entirely preventable.
Roughly a quarter of digital SAT Math questions are student-produced responses — grid-ins — where you type the answer instead of choosing it. There are no choices to eliminate and no partial credit. The arithmetic is usually no harder than the multiple choice around it; the marks are lost on entry rules.
What the box accepts
| Rule | Detail |
|---|---|
| Up to 5 characters | For a positive answer. 6 if the answer is negative, since the minus sign counts. |
| Fractions or decimals | Both accepted. 1/2 and 0.5 are both marked right. |
| No mixed numbers | Type 5/2 or 2.5 — never 2 1/2, which is read as 21/2. |
| No commas | Type 62700, not 62,700. |
| No symbols | No $, no %, no units. Just the number. |
| Negatives allowed | Use the minus sign. Some answers are negative. |
| Any correct value | If a question has more than one right answer, enter one of them. |
The rounding rule that costs the most marks
If your answer does not fit in the box, you may round or truncate — but you must fill the whole box. For 2/3, entering .666 or .667 is accepted; entering .67 is not, because you had room for more digits and did not use them.
The safe habit: if a value is an exact fraction, enter the fraction. 2/3 is always right and never needs rounding. Students who default to decimals create a rounding decision they did not need to have.
The five that catch people
- Mixed numbers. 2 1/2 reads as 21/2. Enter 2.5 or 5/2.
- Under-filled decimals. .67 for 2/3 is wrong; .667 is right.
- Commas in large numbers. 62,700 is not a number to the box.
- Units and symbols. "12 cm" and "$12" are both wrong. Enter 12.
- Answering the wrong thing. The question asked for x; you solved for x and then, out of habit, computed 2x+1. Re-read the last line of the stem before typing.
Because there are no choices, check differently
On a multiple choice question the options are a sanity check — if your answer is not among them, you know immediately. A grid-in removes that safety net, so build your own:
- Substitute back. Put your answer into the original equation. Ten seconds.
- Ask whether it is plausible. A probability above 1, a negative length or a 4,000% increase means something went wrong.
- Re-read what was asked. This catches more grid-in errors than any arithmetic check.
Should you use Desmos on grid-ins?
Often, yes — and more than on multiple choice, because there are no options to work backwards from. Graphing an equation and reading a root or an intersection is faster and safer than solving it by hand under time pressure.
Questions people ask
- Can you enter fractions in SAT grid-ins?
- Yes. Fractions and decimals are both accepted — 1/2 and 0.5 are equally correct. Mixed numbers are not: 2 1/2 must be entered as 5/2 or 2.5.
- How do you round a grid-in answer?
- Fill the whole box. For 2/3, .666 or .667 is accepted but .67 is not. Entering the exact fraction avoids the problem entirely.
- Is there a penalty for a wrong grid-in?
- No. There is no penalty for a wrong answer anywhere on the SAT, so always enter something.
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