diff --git a/src/parse.rs b/src/parse.rs
index c6308bb..4688d51 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -21,9 +21,9 @@ pub fn parse(input: &str) -> Result<Vec<NonMetricQuantity>, ParseError> {
 	for token in tokenize(input) {
 		match (&state, token) {
 			(Expect::Number, Token::Number(number)) => {
-				let number = match number.trim().parse() {
-					Ok(number) => number,
-					Err(_) => {
+				let number = match parse_number(&number) {
+					Some(number) => number,
+					None => {
 						return Err(ParseError::NotValidNumber(number));
 					}
 				};
@@ -63,6 +63,11 @@ pub fn parse(input: &str) -> Result<Vec<NonMetricQuantity>, ParseError> {
 	Ok(quantities)
 }
 
+fn parse_number(input: &str) -> Option<f64> {
+	let no_whitespace: String = input.chars().filter(|c| !c.is_whitespace()).collect();
+	no_whitespace.parse().ok()
+}
+
 fn parse_unit(input: &str) -> Option<NonMetric> {
 	match input {
 		// Length
@@ -187,6 +192,9 @@ mod test {
 			NonMetricQuantity { amount: 5.0, unit: NonMetric::Foot },
 			NonMetricQuantity { amount: 8.0, unit: NonMetric::Inch },
 		]));
+		assert_eq!(parse("20 000 lbs"), Ok(vec![
+			NonMetricQuantity { amount: 20_000.0, unit: NonMetric::Pound },
+		]));
 
 		assert_eq!(parse("12.0."), Err(ParseError::NotValidNumber("12.0.".to_string())));
 		assert_eq!(parse("ft"), Err(ParseError::UnexpectedUnit("ft".to_string())));
@@ -194,6 +202,17 @@ mod test {
 		assert_eq!(parse("12"), Err(ParseError::ExpectedUnit));
 	}
 
+	#[test]
+	fn numbers() {
+		assert_eq!(parse_number(""), None);
+		assert_eq!(parse_number("1"), Some(1.0));
+		assert_eq!(parse_number("1.0"), Some(1.0));
+		assert_eq!(parse_number("0.1"), Some(0.1));
+		assert_eq!(parse_number("0.1."), None);
+		assert_eq!(parse_number("-10"), Some(-10.0));
+		assert_eq!(parse_number("10\t00\u{1680}000"), Some(10_00_000.0));
+	}
+
 	#[test]
 	fn units() {
 		// Length
@@ -243,6 +262,8 @@ mod test {
 		assert_eq!(tokenize("10"), vec![Token::Number("10".to_string())]);
 		assert_eq!(tokenize("  10  "), vec![Token::Number("10".to_string())]);
 		assert_eq!(tokenize("10 000"), vec![Token::Number("10 000".to_string())]);
+		assert_eq!(tokenize("10\t000"), vec![Token::Number("10\t000".to_string())]);
+		assert_eq!(tokenize("10\u{1680}000"), vec![Token::Number("10\u{1680}000".to_string())]);
 		assert_eq!(tokenize("10.0.1"), vec![Token::Number("10.0.1".to_string())]);
 		assert_eq!(tokenize("ft"), vec![Token::Unit("ft".to_string())]);
 		assert_eq!(