No, and this is the most costly grid-in error. Entering 1 1/2 is read as the fraction 11/2, a completely different number. Always convert mixed numbers to an improper fraction such as 3/2 or a decimal such as 1.5.
This error is expensive precisely because it looks correct on the screen. The problem is solved, the arithmetic is right, and the entry is wrong, so nothing about reviewing your work catches it. Build the habit of converting during the solve rather than at the point of entry.
The full picture, with the surrounding detail, is in SAT Grid-In Questions: The Format Rules Explained.