# Fill in the Blank

> Choose the right input and decide when equivalent mathematical answers count.

Source: https://www.curacourse.com/help/fill-in-the-blank

## What this block does
A Fill in the Blank Question embeds answer inputs within a sentence, expression, or worked problem. Each blank has its own input kind and accepted answers.

## Set up a blank
Insert **Fill in the Blank Question**, write the prompt, and configure each blank. Choose **text**, **number**, **dropdown**, or **math**. Add accepted answers; dropdown answers refer to the configured choices. For text answers, configure case, whitespace, and single-letter mistake handling when appropriate. For numerical comparisons, choose a tolerance suited to the precision you require.

## Choose a math comparison mode
| Mode | Use it when |
| --- | --- |
| Exact form | The student must use the mathematical structure you asked for. |
| Equivalent | Algebraically equivalent expressions should count, such as `2x` and `x+x`. |
| Numeric | Both sides should evaluate to the same number within the configured tolerance. |
| Simplified | The expression must be equivalent and already simplified. |

## Example: an equivalent answer is not always the goal
For “Write an expression for twice x,” equivalent mode can accept **x+x** when the expected answer is **2x**. For “Simplify x+x,” simplified mode asks for the simplified expression. Choose the mode from the skill you are assessing, not simply to make the checker more lenient.

## Troubleshooting
If a mathematically valid answer fails, first check the comparison mode. Exact form can reject a rearranged expression. Simplified mode can reject an equivalent answer that still needs simplification. For decimal answers, check the tolerance and whether the blank is a number or a math input.