diff --git a/src/lib.rs b/src/lib.rs
index 2d3f54f..9693ea7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -58,6 +58,26 @@ enum SmallUintType {
     Heap((*mut u32, usize)),
 }
 
+// TODO: Need to reimplement Debug, to_str_radix, and from_str_radix without num-bigint feature for
+// SmallInt and SmallUint
+
+// TODO: add native operations for SmallInt and SmallUint
+
+#[cfg(feature="num-bigint")]
+impl core::fmt::Debug for SmallInt {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", BigInt::from(self))
+    }
+}
+
+#[cfg(feature="num-bigint")]
+impl core::fmt::Debug for SmallUint {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", BigUint::from(self))
+    }
+}
+
+
 impl Drop for SmallInt {
     fn drop(&mut self) {
         if let Self(SmallIntType::Heap((r, s))) = self {
@@ -228,9 +248,9 @@ impl TryFrom<SmallInt> for SmallUint {
 }
 
 #[cfg(feature = "num-bigint")]
-impl From<BigInt> for SmallInt {
-    fn from(b: BigInt) -> Self {
-        match (&b).try_into() {
+impl From<&BigInt> for SmallInt {
+    fn from(b: &BigInt) -> Self {
+        match b.try_into() {
             Ok(i) => Self(SmallIntType::Inline(i)),
             Err(_) => {
                 let (sign, vec) = b.to_u32_digits();
@@ -249,8 +269,8 @@ impl From<BigInt> for SmallInt {
 }
 
 #[cfg(feature = "num-bigint")]
-impl From<SmallInt> for BigInt {
-    fn from(s: SmallInt) -> Self {
+impl From<&SmallInt> for BigInt {
+    fn from(s: &SmallInt) -> Self {
         match s.0 {
             SmallIntType::Inline(i) => Self::from(i),
             SmallIntType::Heap((r, s)) => {
@@ -271,9 +291,9 @@ impl From<SmallInt> for BigInt {
 }
 
 #[cfg(feature = "num-bigint")]
-impl From<BigUint> for SmallUint {
-    fn from(b: BigUint) -> Self {
-        match (&b).try_into() {
+impl From<&BigUint> for SmallUint {
+    fn from(b: &BigUint) -> Self {
+        match b.try_into() {
             Ok(i) => Self(SmallUintType::Inline(i)),
             Err(_) => {
                 let vec = b.to_u32_digits();
@@ -286,8 +306,8 @@ impl From<BigUint> for SmallUint {
 }
 
 #[cfg(feature = "num-bigint")]
-impl From<SmallUint> for BigUint {
-    fn from(s: SmallUint) -> Self {
+impl From<&SmallUint> for BigUint {
+    fn from(s: &SmallUint) -> Self {
         match s.0 {
             SmallUintType::Inline(i) => Self::from(i),
             SmallUintType::Heap((r, s)) => {
@@ -337,10 +357,11 @@ mod conversion_tests {
     #[cfg(feature = "num-bigint")]
     fn test_bigint() {
         let i = BigInt::new(Sign::Plus, vec![5, 4, 8, 3, 2, 9, 3]);
-        let s = SmallInt::from(i);
+        let s = SmallInt::from(&i);
         assert_eq!(
-            BigInt::from(s).to_u32_digits(),
+            BigInt::from(&s).to_u32_digits(),
             (Sign::Plus, vec![5, 4, 8, 3, 2, 9, 3])
         );
     }
+
 }