diff --git a/src/quantity/quantity.rs b/src/quantity/quantity.rs
index dfff1b4..7bf2779 100644
--- a/src/quantity/quantity.rs
+++ b/src/quantity/quantity.rs
@@ -111,6 +111,7 @@ impl Quantity {
 	pub fn is_negative(&self) -> bool { self.v.is_negative() }
 	pub fn is_positive(&self) -> bool { self.v.is_positive() }
 	pub fn unitless(&self) -> bool { self.u.unitless() }
+	pub fn unit(&self) -> &Unit { &self.u }
 
 	quant_foward!(fract);
 	quant_foward!(abs);
diff --git a/src/tests.rs b/src/tests.rs
index dbca87b..8c24f00 100644
--- a/src/tests.rs
+++ b/src/tests.rs
@@ -191,7 +191,7 @@ fn units() {
 
 	//good_expr("2 m", "rt (4m^2)");
 
-	//bad_expr("m + s");
-	//bad_expr("m ^ s");
+	bad_expr("m + s");
+	bad_expr("m ^ s");
 	//bad_expr("m ^ pi");
 }
\ No newline at end of file
diff --git a/src/tokens/function.rs b/src/tokens/function.rs
index 35720c6..b958c46 100644
--- a/src/tokens/function.rs
+++ b/src/tokens/function.rs
@@ -70,6 +70,10 @@ impl Function {
 		let a = args[0].as_number();
 		let Token::Number(q) = a else {panic!()};
 
+		if !q.unitless() {
+			return Err(());
+		}
+
 		match self {
 			Function::Abs => { return Ok(Token::Number(q.abs())); },
 			Function::Floor => { return Ok(Token::Number(q.floor())); },
diff --git a/src/tokens/operator.rs b/src/tokens/operator.rs
index 2053691..6488cd8 100644
--- a/src/tokens/operator.rs
+++ b/src/tokens/operator.rs
@@ -369,6 +369,11 @@ impl Operator{
 				while i < args.len() {
 					let j = args[i].as_number();
 					if let Token::Number(v) = j {
+
+						if sum.unit() != v.unit() {
+							return Err(());
+						}
+
 						sum += v;
 					} else {
 						panic!();
@@ -399,6 +404,11 @@ impl Operator{
 
 				if let Token::Number(va) = a {
 					if let Token::Number(vb) = b {
+
+						if !(va.unitless() && vb.unitless()) {
+							return Err(());
+						}
+
 						if vb <= Quantity::new_rational(1f64).unwrap() { return Err(()); }
 						if va.fract() != Quantity::new_rational(0f64).unwrap() { return Err(()); }
 						if vb.fract() != Quantity::new_rational(0f64).unwrap() { return Err(()); }
@@ -415,6 +425,11 @@ impl Operator{
 
 				if let Token::Number(va) = a {
 					if let Token::Number(vb) = b {
+
+						if va.unit() != vb.unit() {
+							return Err(());
+						}
+
 						let p = va.pow(vb);
 						if p.is_nan() {return Err(());}
 						return Ok(Token::Number(p));
@@ -427,6 +442,11 @@ impl Operator{
 				let args = args[0].as_number();
 
 				if let Token::Number(v) = args {
+
+					if !v.unitless() {
+						return Err(());
+					}
+
 					if !v.fract().is_zero() { return Err(()); }
 					if v > Quantity::new_rational(50_000f64).unwrap() { return Err(()); }