diff --git a/doc/grammar.bnf b/doc/grammar.bnf
index 63c9720..d9ede09 100644
--- a/doc/grammar.bnf
+++ b/doc/grammar.bnf
@@ -1,4 +1,4 @@
 MODULE ::= INSTR*
 INSTR ::= EXPR semicolon
 EXPR ::= BUILTIN
-BUILTIN ::= bool
+BUILTIN ::= bool | float | int
diff --git a/src/ast/lexer.rs b/src/ast/lexer.rs
index e1e1886..f1e9bee 100644
--- a/src/ast/lexer.rs
+++ b/src/ast/lexer.rs
@@ -1,8 +1,8 @@
-use crate::ast::node;
+use crate::ast::node::Node;
 
 struct Token {
     position: usize,
-    value: String,
+    value: String
 }
 
 pub struct Lexer {
@@ -53,6 +53,79 @@ impl Lexer {
         false
     }
 
+
+    fn scan_int(&self) -> Option<Token> {
+        let mut value = String::from("");
+        
+        if let Some('-') = self.text.chars().nth(self.cursor) {
+            value.push('-');
+        }
+
+        for c in self.text.chars().skip(self.cursor + value.len()) {
+            if c.is_digit(10) {
+                value.push(c);
+            } else {
+                break;
+            }
+        }
+        
+        if value.len() > 0 {
+            Some(Token {
+                position: self.cursor + value.len(),
+                value
+            })
+        } else {
+            None
+        } 
+    }
+
+    fn scan_float(&self) -> Option<Token> {
+        let mut value = String::from("");
+        
+        if let Some('-') = self.text.chars().nth(self.cursor) {
+            value.push('-');
+        }
+
+        for c in self.text.chars().skip(self.cursor + value.len()) {
+            if c.is_digit(10) {
+                value.push(c);
+            } else {
+                break;
+            }
+        }
+        
+        if let Some('.') = self.text.chars().nth(self.cursor + value.len()) {
+            value.push('.');
+        } else {
+            return None;
+        }
+
+        for c in self.text.chars().skip(self.cursor + value.len()) {
+            if c.is_digit(10) {
+                value.push(c);
+            } else {
+                break;
+            }
+        }
+        
+        if value.len() > 0 && value != "." {
+            if value.chars().nth(0).unwrap() == '.' {
+                value = format!("0{}", value);
+            }
+
+            if value.chars().last().unwrap() == '.' {
+                value = format!("{}0", value);
+            }
+
+            Some(Token {
+                position: self.cursor + value.len(),
+                value
+            })
+        } else {
+            None
+        } 
+    }
+
     fn scan_text(&self, text: &str) -> Option<Token> {
         let c = self.cursor;
 
@@ -112,24 +185,38 @@ impl Lexer {
 }
 
 impl Iterator for Lexer {
-    type Item = node::Node;
+    type Item = Node;
 
     fn next(&mut self) -> Option<Self::Item> {
         self.skip_spaces();
 
         if let Some(token) = self.scan_keyword("true") {
             self.cursor = token.position;
-            return Some(node::Node::Bool(token.value == "true"));
+            return Some(Node::Bool(token.value == "true"));
         }
 
         if let Some(token) = self.scan_keyword("false") {
             self.cursor = token.position;
-            return Some(node::Node::Bool(token.value == "true"));
+            return Some(Node::Bool(token.value == "true"));
         }
 
         if let Some(token) = self.scan_text(";") {
             self.cursor = token.position;
-            return Some(node::Node::Semicolon);
+            return Some(Node::Semicolon);
+        }
+
+        if let Some(token) = self.scan_float() {
+            if let Ok(val) = token.value.parse::<f64>() {
+                self.cursor = token.position;
+                return Some(Node::Float(val));
+            }
+        }
+
+        if let Some(token) = self.scan_int() {
+            if let Ok(val) = token.value.parse::<i32>() {
+                self.cursor = token.position;
+                return Some(Node::Int(val));
+            }
         }
 
         None
@@ -140,8 +227,9 @@ impl Iterator for Lexer {
 mod test {
     use super::*;
     use crate::ast::error;
+    use crate::ast::node::Node;
 
-    fn lexer_run(lexer: &mut Lexer, text: &str) -> Result<Vec<node::Node>, error::AstError> {
+    fn lexer_run(lexer: &mut Lexer, text: &str) -> Result<Vec<Node>, error::AstError> {
         lexer.prepare(text);
         let result = lexer.collect();
 
@@ -168,8 +256,8 @@ mod test {
         let mut lex = Lexer::new();
         let res = lexer_run(&mut lex, "true false").unwrap();
         assert_eq!(2, res.len());
-        assert_eq!("Bool(true)", format!("{:?}", res.get(0).unwrap()));
-        assert_eq!("Bool(false)", format!("{:?}", res.get(1).unwrap()));
+        assert_eq!(Node::Bool(true), *res.get(0).unwrap());
+        assert_eq!(Node::Bool(false), *res.get(1).unwrap());
     }
 
     #[test]
@@ -177,8 +265,8 @@ mod test {
         let mut lex = Lexer::new();
         let res = lexer_run(&mut lex, "true;").unwrap();
         assert_eq!(2, res.len());
-        assert_eq!("Bool(true)", format!("{:?}", res.get(0).unwrap()));
-        assert_eq!("Semicolon", format!("{:?}", res.get(1).unwrap()));
+        assert_eq!(Node::Bool(true), *res.get(0).unwrap());
+        assert_eq!(Node::Semicolon, *res.get(1).unwrap());
     }
 
     #[test]
@@ -203,8 +291,33 @@ mod test {
         let mut lex = Lexer::new();
         let res = lexer_run(&mut lex, " ;; ")?;
         assert_eq!(2, res.len());
-        assert_eq!("Semicolon", format!("{:?}", res.get(0).unwrap()));
-        assert_eq!("Semicolon", format!("{:?}", res.get(1).unwrap()));
+        assert_eq!(Node::Semicolon, *res.get(0).unwrap());
+        assert_eq!(Node::Semicolon, *res.get(1).unwrap());
+        Ok(())
+    }
+    
+    #[test]
+    fn test_integers() -> Result<(), error::AstError> {
+        let mut lex = Lexer::new();
+        let res = lexer_run(&mut lex, " 4 -2 328")?;
+        assert_eq!(3, res.len());
+        assert_eq!(Node::Int(4), *res.get(0).unwrap());
+        assert_eq!(Node::Int(-2), *res.get(1).unwrap());
+        assert_eq!(Node::Int(328), *res.get(2).unwrap());
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_floats() -> Result<(), error::AstError> {
+        let mut lex = Lexer::new();
+        let res = lexer_run(&mut lex, " 2.0 .7 5. -3.14 ")?;
+        assert_eq!(4, res.len());
+        assert_eq!(Node::Float(2.0), *res.get(0).unwrap());
+        assert_eq!(Node::Float(0.7), *res.get(1).unwrap());
+        assert_eq!(Node::Float(5.0), *res.get(2).unwrap());
+        assert_eq!(Node::Float(-3.14), *res.get(3).unwrap());
+
         Ok(())
     }
 }
diff --git a/src/ast/node.rs b/src/ast/node.rs
index f3a43ec..b1ae045 100644
--- a/src/ast/node.rs
+++ b/src/ast/node.rs
@@ -3,6 +3,8 @@
 pub enum Node {
     Module(String, Vec<Node>),
     Bool(bool),
+    Int(i32),
+    Float(f64),
     Semicolon
 }
 
diff --git a/src/ast/parser.rs b/src/ast/parser.rs
index faab2eb..28ef6a8 100644
--- a/src/ast/parser.rs
+++ b/src/ast/parser.rs
@@ -1,5 +1,5 @@
 use crate::ast::{
-    node,
+    node::Node,
     lexer,
     error
 };
@@ -9,7 +9,7 @@ pub struct Parser {
     lexer: lexer::Lexer
 }
 
-type ParseResult = Result<Option<node::Node>, error::AstError>;
+type ParseResult = Result<Option<Node>, error::AstError>;
 
 impl Parser {
     pub fn new(module_name: &str, lex: lexer::Lexer) -> Self {
@@ -24,7 +24,7 @@ impl Parser {
     }
 
     fn parse_module(&mut self) -> ParseResult {
-        let mut children: Vec<node::Node> = vec![];
+        let mut children: Vec<Node> = vec![];
 
         loop {
             match self.parse_instr() {
@@ -41,7 +41,7 @@ impl Parser {
             });
         }
 
-        let n = node::Node::Module(self.module_name.clone(), children);
+        let n = Node::Module(self.module_name.clone(), children);
         Ok(Some(n))
     }
 
@@ -49,7 +49,7 @@ impl Parser {
         match self.parse_expr() {
             Ok(Some(expr)) => {
                 match self.lexer.next() {
-                    Some(node::Node::Semicolon) => Ok(Some(expr)),
+                    Some(Node::Semicolon) => Ok(Some(expr)),
                     None => Ok(None),
                     _ => Err(error::AstError {
                         msg: String::from("missing semicolon"),
@@ -68,8 +68,14 @@ impl Parser {
 
     fn parse_builtin(&mut self) -> ParseResult {
         match self.lexer.next() {
-            Some(node::Node::Bool(value))
-                => Ok(Some(node::Node::Bool(value))),
+            Some(Node::Int(value))
+                => Ok(Some(Node::Int(value))),
+
+            Some(Node::Float(value))
+                => Ok(Some(Node::Float(value))),
+
+            Some(Node::Bool(value))
+                => Ok(Some(Node::Bool(value))),
 
             Some(other) => {
                 Err(error::AstError {
@@ -86,11 +92,10 @@ impl Parser {
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::ast::node::Node;
 
     type TestResult = Result<(), String>;
 
-    fn test_parser(oracle: node::Node, source: &str) -> TestResult {
+    fn test_parser(oracle: Node, source: &str) -> TestResult {
         let mut lex = lexer::Lexer::new();
         lex.prepare(source);
         let mut parser = Parser::new("mod", lex);
@@ -140,4 +145,23 @@ mod test {
 
         Ok(())
     }
+
+    #[test]
+    fn numbers() -> TestResult {
+        test_parser(
+            Node::Module("mod".to_owned(), vec![
+                Node::Float(27.3)
+            ]),
+            " 27.3; "
+        )?;
+
+        test_parser(
+            Node::Module("mod".to_owned(), vec![
+                Node::Int(-27)
+            ]),
+            " -27; "
+        )?;
+
+        Ok(())
+    }
 }
diff --git a/src/eval/evaluator.rs b/src/eval/evaluator.rs
index eb94a49..b5ee2fe 100644
--- a/src/eval/evaluator.rs
+++ b/src/eval/evaluator.rs
@@ -29,7 +29,11 @@ impl Evaluator {
 
                 Ok(res)
             },
+            
             Node::Bool(value) => Ok(Some(Value::Bool(*value))),
+            Node::Int(value) => Ok(Some(Value::Int(*value))),
+            Node::Float(value) => Ok(Some(Value::Float(*value))),
+
             _ => Ok(None)
         }
     }
@@ -65,7 +69,10 @@ mod test {
                         Ok(())
                     }
                 } else {
-                    Ok(())
+                    Err(Box::new(EvalError {
+                        msg: format!("unexpected: {:?}", value),
+                        line: 0
+                    }))
                 }
             },
             None => Ok(())
@@ -79,4 +86,12 @@ mod test {
 
         Ok(())
     }
+
+    #[test]
+    fn numbers() -> TestResult {
+        test_eval_value(Value::Float(-271.4), " -271.4; ")?;
+        test_eval_value(Value::Int(333), " 333; ")?;
+
+        Ok(())
+    }
 }
diff --git a/src/eval/value.rs b/src/eval/value.rs
index 8d74361..53559c9 100644
--- a/src/eval/value.rs
+++ b/src/eval/value.rs
@@ -1,6 +1,8 @@
 #[derive(PartialEq)]
 #[derive(Debug)]
 pub enum Value {
-    Bool(bool)
+    Bool(bool),
+    Int(i32),
+    Float(f64)
 }