Add palindrome checking function in Ruby

maths/palindrome.rb

@@ -0,0 +1,48 @@
+# Palindrome Number Checking in Ruby
+
+# Checks if a given integer is a palindrome without converting it to a string.
+# A palindrome is a number that reads the same backward as forward.
+# Negative numbers are not considered palindromes by this definition.
+#
+# @param number [Integer] The integer to check.
+# @return [Boolean] true if the number is a palindrome, false otherwise.
+#
+# Examples:
+# is_palindrome(121)  #=> true
+# is_palindrome(123)  #=> false
+# is_palindrome(7)    #=> true
+# is_palindrome(0)    #=> true
+# is_palindrome(-121) #=> false
+def is_palindrome(number)
+  # Negative numbers are not considered palindromes
+  return false if number < 0
+
+  # Single digits are always palindromes
+  # return true if number < 10 # This line is optional but efficient
+
+  original_number = number
+  reversed_number = 0
+
+  # Loop while the number is greater than 0
+  while number > 0
+    # Get the last digit
+    remainder = number % 10
+
+    # Build the reversed number
+    reversed_number = (reversed_number * 10) + remainder
+
+    # Remove the last digit using integer division
+    number /= 10
+  end
+
+  # Return true if the original and reversed numbers are the same
+  original_number == reversed_number
+end
+
+# --- Examples ---
+puts "Is 121 a palindrome? #{is_palindrome(121)}"   # Output: true
+puts "Is 123 a palindrome? #{is_palindrome(123)}"   # Output: false
+puts "Is 7 a palindrome? #{is_palindrome(7)}"     # Output: true
+puts "Is 0 a palindrome? #{is_palindrome(0)}"     # Output: true
+puts "Is -101 a palindrome? #{is_palindrome(-101)}" # Output: false
+puts "Is 1221 a palindrome? #{is_palindrome(1221)}"  # Output: true