diff --git a/05-é-primo/index.html b/05-é-primo/index.html
index cd11c0c..e7ad135 100644
--- a/05-é-primo/index.html
+++ b/05-é-primo/index.html
@@ -16,6 +16,26 @@
         */
         function isPrime(number) {
             // implementar logica aqui
+            if (number === 2 || number === 3) return true
+            if (number % 2 === 0 || number < 2) return false
+
+            var s = 0,
+                d = number - 1
+            while ((d & 1) == 0) {
+                d >>= 1
+                ++s
+            }
+
+            let base = 2
+            var x = Math.pow(base, d) % number
+
+            if (x == 1 || x == number - 1) return true
+
+            for (var i = 1; i <= s; i++) {
+                x = (x * x) % number
+
+                if (x === number - 1) return true
+            }
             return false
         }