diff --git a/math/src/ring/impl_u64/rescaling_rns.rs b/math/src/ring/impl_u64/rescaling_rns.rs
index e4884ef..c1526e3 100644
--- a/math/src/ring/impl_u64/rescaling_rns.rs
+++ b/math/src/ring/impl_u64/rescaling_rns.rs
@@ -14,6 +14,7 @@ impl RingRNS<u64> {
         buf: &mut PolyRNS<u64>,
         b: &mut PolyRNS<u64>,
     ) {
+        debug_assert!(self.level() != 0, "invalid call: self.level()=0");
         debug_assert!(
             self.level() <= a.level(),
             "invalid input a: self.level()={} > a.level()={}",
@@ -21,10 +22,10 @@ impl RingRNS<u64> {
             a.level()
         );
         debug_assert!(
-            b.level() >= a.level() - 1,
-            "invalid input b: b.level()={} < a.level()-1={}",
+            b.level() >= self.level() - 1,
+            "invalid input b: b.level()={} < self.level()-1={}",
             b.level(),
-            a.level() - 1
+            self.level() - 1
         );
 
         let level = self.level();
@@ -102,28 +103,31 @@ impl RingRNS<u64> {
         buf: &mut PolyRNS<u64>,
         c: &mut PolyRNS<u64>,
     ) {
-
-        println!("{:?}", buf);
-
         debug_assert!(
-            self.level() <= a.level(),
+            nb_moduli <= self.level(),
+            "invalid input nb_moduli: nb_moduli={} > a.level()={}",
+            nb_moduli,
+            a.level()
+        );
+        debug_assert!(
+            a.level() <= self.level(),
             "invalid input a: self.level()={} > a.level()={}",
             self.level(),
             a.level()
         );
         debug_assert!(
-            c.level() >= a.level() - 1,
-            "invalid input b: b.level()={} < a.level()-1={}",
-            c.level(),
+            buf.level() >= self.level() - 1,
+            "invalid input buf: buf.level()={} < a.level()-1={}",
+            buf.level(),
             a.level() - 1
         );
         debug_assert!(
-            nb_moduli <= a.level(),
-            "invalid input nb_moduli: nb_moduli={} > a.level()={}",
-            nb_moduli,
-            a.level()
+            c.level() >= self.level() - nb_moduli,
+            "invalid input c: c.level()={} < c.level()-nb_moduli={}",
+            c.level(),
+            a.level() - nb_moduli
         );
-
+    
         if nb_moduli == 0 {
             if a != c {
                 c.copy(a);
@@ -140,11 +144,21 @@ impl RingRNS<u64> {
                 });
                 self.at_level(self.level() - nb_moduli).ntt::<false>(buf, c);
             } else {
-                self.div_floor_by_last_modulus::<false>(a, buf, c);
-                (1..nb_moduli).for_each(|i| {
+
+                let empty_buf: &mut PolyRNS<u64> = &mut PolyRNS::<u64>::default();
+
+                if nb_moduli == 1{
+                    self.div_floor_by_last_modulus::<false>(a, empty_buf, c);
+                }else{
+                    self.div_floor_by_last_modulus::<false>(a, empty_buf, buf);
+                }
+                
+                (1..nb_moduli-1).for_each(|i| {
                     self.at_level(self.level() - i)
-                        .div_floor_by_last_modulus_inplace::<false>(buf, c)
+                        .div_floor_by_last_modulus_inplace::<false>(empty_buf, buf);
                 });
+
+                self.at_level(self.level()-nb_moduli+1).div_floor_by_last_modulus::<false>(buf, empty_buf, c);
             }
         }
     }
@@ -168,17 +182,20 @@ impl RingRNS<u64> {
             nb_moduli,
             a.level()
         );
+        if nb_moduli == 0{
+            return
+        }
         if NTT {
             self.intt::<false>(a, buf);
             (0..nb_moduli).for_each(|i| {
                 self.at_level(self.level() - i)
                     .div_floor_by_last_modulus_inplace::<false>(&mut PolyRNS::<u64>::default(), buf)
             });
-            self.at_level(self.level() - nb_moduli).ntt::<false>(buf, a);
+            self.at_level(self.level() - nb_moduli+1).ntt::<false>(buf, a);
         } else {
             (0..nb_moduli).for_each(|i| {
                 self.at_level(self.level() - i)
-                    .div_floor_by_last_modulus_inplace::<false>(buf, a)
+                    .div_floor_by_last_modulus_inplace::<false>(buf, a);
             });
         }
     }
diff --git a/math/tests/rescaling_rns.rs b/math/tests/rescaling_rns.rs
index 5dae27b..8814bc3 100644
--- a/math/tests/rescaling_rns.rs
+++ b/math/tests/rescaling_rns.rs
@@ -10,14 +10,14 @@ fn rescaling_rns_u64() {
     let moduli: Vec<u64> = vec![0x1fffffffffc80001u64, 0x1fffffffffe00001u64, 0x1fffffffffb40001, 0x1fffffffff500001];
     let ring_rns: RingRNS<u64> = RingRNS::new(n, moduli);
 
-    //test_div_floor_by_last_modulus::<false>(&ring_rns);
-    //test_div_floor_by_last_modulus::<true>(&ring_rns);
+    test_div_floor_by_last_modulus::<false>(&ring_rns);
+    test_div_floor_by_last_modulus::<true>(&ring_rns);
     test_div_floor_by_last_modulus_inplace::<false>(&ring_rns);
-    //test_div_floor_by_last_modulus_inplace::<true>(&ring_rns);
-    //test_div_floor_by_last_moduli::<false>(&ring_rns);
-    //test_div_floor_by_last_moduli::<true>(&ring_rns);
-    //test_div_floor_by_last_moduli_inplace::<false>(&ring_rns);
-    //test_div_floor_by_last_moduli_inplace::<true>(&ring_rns);
+    test_div_floor_by_last_modulus_inplace::<true>(&ring_rns);
+    test_div_floor_by_last_moduli::<false>(&ring_rns);
+    test_div_floor_by_last_moduli::<true>(&ring_rns);
+    test_div_floor_by_last_moduli_inplace::<false>(&ring_rns);
+    test_div_floor_by_last_moduli_inplace::<true>(&ring_rns);
 }
 
 fn test_div_floor_by_last_modulus<const NTT: bool>(ring_rns: &RingRNS<u64>) {
@@ -83,8 +83,6 @@ fn test_div_floor_by_last_modulus_inplace<const NTT: bool>(ring_rns: &RingRNS<u6
         .at_level(a.level())
         .to_bigint_inplace(&a, 1, &mut coeffs_a);
 
-        println!("{:?}", &coeffs_a[..8]);
-
     // Performs c = intt(ntt(a) / q_level)
     if NTT {
         ring_rns.ntt_inplace::<false>(&mut a);
@@ -112,9 +110,6 @@ fn test_div_floor_by_last_modulus_inplace<const NTT: bool>(ring_rns: &RingRNS<u6
         }
     });
 
-    println!("{:?}", &coeffs_a[..8]);
-    println!("{:?}", &coeffs_c[..8]);
-
     assert!(coeffs_a == coeffs_c, "test_div_floor_by_last_modulus_inplace");
 }
 
@@ -122,11 +117,11 @@ fn test_div_floor_by_last_moduli<const NTT: bool>(ring_rns: &RingRNS<u64>) {
     let seed: [u8; 32] = [0; 32];
     let mut source: Source = Source::new(seed);
 
-    let nb_moduli: usize = ring_rns.level()-1;
+    let nb_moduli: usize = ring_rns.level();
 
     let mut a: PolyRNS<u64> = ring_rns.new_polyrns();
     let mut b: PolyRNS<u64> = ring_rns.new_polyrns();
-    let mut c: PolyRNS<u64> = ring_rns.at_level(ring_rns.level() - 1).new_polyrns();
+    let mut c: PolyRNS<u64> = ring_rns.at_level(ring_rns.level() - nb_moduli).new_polyrns();
 
     // Allocates a random PolyRNS
     ring_rns.fill_uniform(&mut source, &mut a);
@@ -156,7 +151,8 @@ fn test_div_floor_by_last_moduli<const NTT: bool>(ring_rns: &RingRNS<u64>) {
 
     // Performs floor division on a
     let mut scalar_big = BigInt::from(1);
-    (0..nb_moduli).for_each(|i|{scalar_big *= BigInt::from(ring_rns.0[ring_rns.level()].modulus.q)});
+    (0..nb_moduli).for_each(|i|{scalar_big *= BigInt::from(ring_rns.0[ring_rns.level()-i].modulus.q)});
+   
     coeffs_a.iter_mut().for_each(|a| {
         // Emulates floor division in [0, q-1] and maps to [-(q-1)/2, (q-1)/2-1]
         *a /= &scalar_big;
@@ -172,7 +168,7 @@ fn test_div_floor_by_last_moduli_inplace<const NTT: bool>(ring_rns: &RingRNS<u64
     let seed: [u8; 32] = [0; 32];
     let mut source: Source = Source::new(seed);
 
-    let nb_moduli: usize = ring_rns.level()-1;
+    let nb_moduli: usize = ring_rns.level();
 
     let mut a: PolyRNS<u64> = ring_rns.new_polyrns();
     let mut b: PolyRNS<u64> = ring_rns.new_polyrns();
@@ -205,7 +201,7 @@ fn test_div_floor_by_last_moduli_inplace<const NTT: bool>(ring_rns: &RingRNS<u64
 
     // Performs floor division on a
     let mut scalar_big = BigInt::from(1);
-    (0..nb_moduli).for_each(|i|{scalar_big *= BigInt::from(ring_rns.0[ring_rns.level()].modulus.q)});
+    (0..nb_moduli).for_each(|i|{scalar_big *= BigInt::from(ring_rns.0[ring_rns.level()-i].modulus.q)});
     coeffs_a.iter_mut().for_each(|a| {
         // Emulates floor division in [0, q-1] and maps to [-(q-1)/2, (q-1)/2-1]
         *a /= &scalar_big;