To find out what plus 1.78 equals 0.35, you can set up the equation:
\[ x + 1.78 = 0.35 \]
To solve for \( x \), subtract 1.78 from both sides:
\[ x = 0.35 - 1.78 \]
Now perform the subtraction:
\[ x = 0.35 - 1.78 = -1.43 \]
So, \( -1.43 \) plus 1.78 equals 0.35.