diff --git a/README.md b/README.md
index 3a613b2..bd0cab4 100644
--- a/README.md
+++ b/README.md
@@ -13,7 +13,7 @@ console.log(cc.code('EUR'));
 /*
 {
 	code: 'EUR',
-	number: 978,
+	number: '978',
 	digits: 2,
 	currency: 'Euro',
 	countries: [
@@ -35,7 +35,7 @@ console.log(cc.number(967));
 /*
 {
 	code: 'ZMW',
-	number: 967,
+	number: '967',
 	digits: 2,
 	currency: 'Zambian kwacha',
 	countries: [ 'zambia' ] }
@@ -52,13 +52,13 @@ console.log(cc.country('colombia'));
 [
 	{
 		code: 'COP',
-		number: 170,
+		number: '170',
 		digits: 2,
 		currency: 'Colombian peso',
 		countries: [ 'colombia' ]
 	}, {
 		code: 'COU',
-		number: 970,
+		number: '970',
 		digits: 2,
 		currency: 'Unidad de Valor Real',
 		countries: [ 'colombia' ]
diff --git a/index.js b/index.js
index 804cc31..336b008 100644
--- a/index.js
+++ b/index.js
@@ -18,8 +18,10 @@ var country = function(country) {
   });
 };
 var number = function(number) {
+  number = ('000' + number).slice(-3);
+
   return first(data, function(c) {
-    return c.number === String(number);
+    return c.number === number;
   });
 };
 var codes = function() {
diff --git a/test.js b/test.js
index 1a39ea0..64ec950 100644
--- a/test.js
+++ b/test.js
@@ -1,14 +1,35 @@
 var cc = require('./index');
 var assert = require('assert');
 
-assert(cc.code('EUR').countries.length === 35);
-assert(cc.code('IDR').digits === 2);
-assert(cc.number('967').currency === 'Zambian Kwacha');
-assert(cc.number(967).currency === 'Zambian Kwacha');
-assert(cc.country('Colombia').length === 2);
-assert(cc.country('colombia').length === 2);
-assert(cc.codes().length === 178);
-assert(cc.countries().length === 250);
-assert(cc.numbers().length === 178);
-assert(cc.numbers()[0] === '784');
-assert(cc.data.length == 178);
+// test properties of specific currencies
+
+assert.strictEqual(cc.code('EUR').countries.length, 35, 'The Euro is used by 35 countries');
+assert.strictEqual(cc.code('IDR').digits, 2, 'The Indonesian Rupiah uses a fraction of 2 digits');
+assert.strictEqual(cc.number('967').currency, 'Zambian Kwacha', 'Zambian Kwacha is number 967');
+assert.strictEqual(cc.number('036').code, 'AUD', 'Australian Dollar is AUD');
+assert.strictEqual(cc.country('Colombia').length, 2, 'Colombia has 2 currencies');
+assert.strictEqual(typeof cc.code('JPY').number, 'string', 'Currency numbers are strings');
+
+// test input flexibility
+
+assert.deepStrictEqual(cc.country('colombia'), cc.country('Colombia'), 'Searching by country name is case-insensitive');
+assert.strictEqual(cc.number(967).currency, 'Zambian Kwacha', 'Currencies can be found with a number as integer');
+assert.deepStrictEqual(cc.number(36), cc.number('036'), 'Currencies can be found with a number < 100 as integer');
+assert.deepStrictEqual(cc.number('36'), cc.number('036'), 'Currencies can be found with a number < 100 as string');
+
+// test data across all currencies
+
+cc.numbers().forEach((number) => {
+  assert(number.match(/^[0-9]{3}$/), `"${number}" is expected to be exactly 3 digits`);
+});
+
+cc.codes().forEach((code) => {
+  assert(code.match(/^[A-Z]{3}$/), `"${code}" is expected to be exactly 3 uppercase characters`);
+});
+  
+// test totals
+
+assert.strictEqual(cc.data.length, 179, 'There are a total of 179 currencies');
+assert.strictEqual(cc.codes().length, cc.data.length, 'There are as many currency codes as there are currencies');
+assert.strictEqual(cc.numbers().length, cc.data.length, 'There are as many currency numbers as there are currencies');
+assert.strictEqual(cc.countries().length, 260, 'There are a total of 260 countries');