diff --git a/tests/correctness/math_operators/addition.rs b/tests/correctness/math_operators/addition.rs
index aaedfd004c..8633b6ad71 100644
--- a/tests/correctness/math_operators/addition.rs
+++ b/tests/correctness/math_operators/addition.rs
@@ -1,4 +1,5 @@
 use crate::{compile_and_run, MainType};
+use chrono::TimeZone;
 use num::{Float, NumCast};
 
 //addition tests
@@ -234,7 +235,7 @@ fn add_date_basic() {
     FUNCTION main : DATE
     VAR
         date_var : DATE := D#2021-01-01;
-        date_10_days : DATE := 777600000;
+        date_10_days : DATE := 777600000000000;
         result : DATE;
     END_VAR
         result := date_10_days + date_var;
@@ -245,7 +246,15 @@ fn add_date_basic() {
     let mut main = MainType::default();
 
     let res: u64 = compile_and_run(prog.to_string(), &mut main);
-    assert_eq!(res, 1610236800000);
+    let date_var = chrono::Utc
+        .ymd(2021, 1, 1)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    let date_10_days = chrono::Utc
+        .ymd(1970, 1, 10)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    assert_eq!(res, date_10_days + date_var);
 }
 
 #[test]
diff --git a/tests/correctness/math_operators/division.rs b/tests/correctness/math_operators/division.rs
index 76cd8b77f8..09bc4ba0bc 100644
--- a/tests/correctness/math_operators/division.rs
+++ b/tests/correctness/math_operators/division.rs
@@ -1,4 +1,5 @@
 use crate::{compile_and_run, MainType};
+use chrono::TimeZone;
 use num::{Float, NumCast};
 
 //--------------------------------------------------------------
@@ -196,7 +197,7 @@ fn division_date_basic() {
     FUNCTION main : DATE
     VAR
         date_var : DATE := D#2021-01-01;
-        date_10_days : DATE := 777600000;
+        date_10_days : DATE := 777600000000000;
         result,div_result : DATE;
     END_VAR
         div_result := date_10_days / 2;
@@ -208,7 +209,15 @@ fn division_date_basic() {
     let mut main = MainType::default();
 
     let res: u64 = compile_and_run(prog.to_string(), &mut main);
-    assert_eq!(res, 1609848000000);
+    let date_var = chrono::Utc
+        .ymd(2021, 1, 1)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    let date_10_days = chrono::Utc
+        .ymd(1970, 1, 10)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    assert_eq!(res, date_var + date_10_days / 2);
 }
 
 #[test]
diff --git a/tests/correctness/math_operators/mixed.rs b/tests/correctness/math_operators/mixed.rs
index 1030cb3bef..6f4f115d2e 100644
--- a/tests/correctness/math_operators/mixed.rs
+++ b/tests/correctness/math_operators/mixed.rs
@@ -1,4 +1,5 @@
 use crate::compile_and_run;
+use chrono::TimeZone;
 use num::{Float, NumCast};
 
 #[derive(Default)]
@@ -166,8 +167,8 @@ fn mixed_math_date_basic() {
     FUNCTION main : DATE
     VAR
         date_var : DATE := D#2021-01-01;
-        date_10_days : DATE := 777600000;
-        date_1_day : DATE := 86400;
+        date_10_days : DATE := 777600000000000;
+        date_1_day : DATE := 86400000000000;
         result : DATE;
     END_VAR
         result := date_var + date_10_days * 2 - date_1_day / 2;
@@ -178,7 +179,19 @@ fn mixed_math_date_basic() {
     let mut main = MainType::default();
 
     let res: u64 = compile_and_run(prog.to_string(), &mut main);
-    assert_eq!(res, 1611014356800);
+    let date_var = chrono::Utc
+        .ymd(2021, 1, 1)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    let date_10_days = chrono::Utc
+        .ymd(1970, 1, 10)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    let date_1_day = chrono::Utc
+        .ymd(1970, 1, 2)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    assert_eq!(res, date_var + date_10_days * 2 - date_1_day / 2);
 }
 
 #[test]
@@ -187,8 +200,8 @@ fn mixed_math_dt_basic() {
     FUNCTION main : DT
     VAR
         date_var : DT := D#2021-01-01;
-        date_10_days : DT := 777600000;
-        date_1_day : DT := 86400;
+        date_10_days : DT := 777600000000000;
+        date_1_day : DT := 86400000000000;
         result : DT;
     END_VAR
         result := date_var + date_10_days * 2 - date_1_day / 2;
@@ -199,7 +212,19 @@ fn mixed_math_dt_basic() {
     let mut main = MainType::default();
 
     let res: u64 = compile_and_run(prog.to_string(), &mut main);
-    assert_eq!(res, 1611014356800);
+    let date_var = chrono::Utc
+        .ymd(2021, 1, 1)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    let date_10_days = chrono::Utc
+        .ymd(1970, 1, 10)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    let date_1_day = chrono::Utc
+        .ymd(1970, 1, 2)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    assert_eq!(res, date_var + date_10_days * 2 - date_1_day / 2);
 }
 
 #[test]
diff --git a/tests/correctness/math_operators/multiplication.rs b/tests/correctness/math_operators/multiplication.rs
index 6baeee0ab5..c1e07a07a6 100644
--- a/tests/correctness/math_operators/multiplication.rs
+++ b/tests/correctness/math_operators/multiplication.rs
@@ -1,4 +1,5 @@
 use crate::{assert_almost_eq, compile_and_run, MainType};
+use chrono::TimeZone;
 use num::{Float, NumCast};
 
 //--------------------------------------------------------------
@@ -159,11 +160,11 @@ fn multiplication_date_basic() {
     FUNCTION main : DATE
     VAR
         date_var : DATE := D#2021-01-01;
-        date_10_days : DATE := 777600000;
-        result,div_result : DATE;
+        date_10_days : DATE := 777600000000000;
+        result,mul_result : DATE;
     END_VAR
-        div_result := date_10_days * 2;
-        result := date_var + div_result;
+        mul_result := date_10_days * 2;
+        result := date_var + mul_result;
         main := result;
     END_FUNCTION
     ";
@@ -171,7 +172,15 @@ fn multiplication_date_basic() {
     let mut main = MainType::default();
 
     let res: u64 = compile_and_run(prog.to_string(), &mut main);
-    assert_eq!(res, 1611014400000);
+    let date_var = chrono::Utc
+        .ymd(2021, 1, 1)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    let date_10_days = chrono::Utc
+        .ymd(1970, 1, 10)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    assert_eq!(res, date_var + date_10_days * 2);
 }
 
 #[test]
diff --git a/tests/correctness/math_operators/substraction.rs b/tests/correctness/math_operators/substraction.rs
index 908c55cf2b..a779175a4c 100644
--- a/tests/correctness/math_operators/substraction.rs
+++ b/tests/correctness/math_operators/substraction.rs
@@ -1,4 +1,5 @@
 use crate::{compile_and_run, MainType};
+use chrono::TimeZone;
 use num::{Float, NumCast};
 
 //--------------------------------------------------------------
@@ -207,7 +208,15 @@ fn substract_date_basic() {
     let mut main = MainType::default();
 
     let res: u64 = compile_and_run(prog.to_string(), &mut main);
-    assert_eq!(res, 777600000);
+    let date_var = chrono::Utc
+        .ymd(2021, 1, 1)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    let date_temp = chrono::Utc
+        .ymd(2021, 1, 10)
+        .and_hms(0, 0, 0)
+        .timestamp_nanos() as u64;
+    assert_eq!(res, date_temp - date_var);
 }
 
 #[test]