To find the integer that makes the subtraction sentence true, we need to set up the equation:
\[ 724 - x = -242 \]
To solve for \( x \), we can rearrange the equation:
\[ x = 724 - (-242) \]
This simplifies to:
\[ x = 724 + 242 \]
Now, we calculate:
\[ 724 + 242 = 966 \]
So, the integer that makes the subtraction sentence true is:
966.