diff --git a/maths/prime_number.rb b/maths/prime_number.rb
new file mode 100644
index 0000000..ad5abe7
--- /dev/null
+++ b/maths/prime_number.rb
@@ -0,0 +1,38 @@
+# A ruby program to check a given number is prime or not
+# Mathematical explanation: A number which has only 2 factors i.e., 1 (one) and itself
+
+# Prime number check function
+def is_prime_number(number)
+  primeFlag = false
+  if number>0
+    if number == 1
+    primeFlag = true
+    else
+      factors = 2;
+      while factors.to_i <= number.to_i/2
+        if number.to_i % factors.to_i==0
+        primeFlag = true
+        break
+        end
+        factors+=1
+      end
+    end
+  else
+  primeFlag = true
+  end
+
+  if !primeFlag
+    print "\nThe given number " + number.to_s + " is a Prime."
+  else
+    print "\nThe given number " + number.to_s + " is not a Prime."
+  end
+end
+
+# prime input
+is_prime_number(2)
+
+# Non-prime input
+is_prime_number(20)
+
+# Negative input
+is_prime_number(-21)