Addition and subtraction checks

https://github.com/nus-test/XPress/blob/9b54acb01f375bb16c5942c017f093352ba8ab04/src/main/java/XPress/DataCheckUtils.java#L4

I noticed some integer checking logic in the above method. Could this logic be simplified using [`addExact`](https://docs.oracle.com/javase/8/docs/api/java/lang/Math.html#addExact-int-int-) and similar methods?