diff --git a/src/bigint.rs b/src/bigint.rs
index 3e8b78b..551ecc6 100644
--- a/src/bigint.rs
+++ b/src/bigint.rs
@@ -142,6 +142,7 @@ impl Sub for BigInt {
     type Output = Self;
 
     fn sub(self, rhs: Self) -> Self::Output {
+        // @TODO: handle signs
         let mut out = BigInt::new_empty();
 
         let u_digits = self.inner.len();
@@ -158,10 +159,6 @@ impl Sub for BigInt {
             let a = *self.inner.get(i).unwrap_or(&0usize);
             let b = *rhs.inner.get(i).unwrap_or(&0usize);
 
-            if a == 0 && b == 0 {
-                continue;
-            }
-
             if a > 0 && (a - borrow) >= b {
                 let res = a - b - borrow;
 
@@ -362,6 +359,18 @@ mod tests {
         assert_eq!(int.inner[0], 45usize)
     }
 
+    #[test]
+    fn test_trim_zeros() {
+        let mut lotsoftrailing = BigInt {
+            inner: vec![1, 0, 0, 0, 0, 0, 0, 0, 0],
+            sign: Positive
+        };
+
+        lotsoftrailing.trim_zeros();
+
+        assert_eq!(BigInt::from(1), lotsoftrailing);
+    }
+
     #[test]
     fn test_add() {
         // MAX is 2^Bitsize - 1,
@@ -414,6 +423,17 @@ mod tests {
             diff.inner[0],
             core::usize::MAX - 1
         );
+
+        let a = BigInt {
+            inner: vec![1,0,1],
+            sign: Positive
+        };
+        let b = BigInt::from(2);
+        let diff = a - b;
+        assert_eq!(
+            diff.inner,
+            vec![core::usize::MAX, core::usize::MAX]
+        );
     }
 
     #[test]