diff --git a/src/mock.js b/src/mock.js
index 45bd67e7000..8348821e111 100644
--- a/src/mock.js
+++ b/src/mock.js
@@ -51,10 +51,10 @@ function addMockFunctionsToSchema({ schema, mocks = {}, preserveResolvers = fals
   });
 
   const defaultMockMap = new Map();
-  defaultMockMap.set('Int', () => Math.round(Math.random * 200) - 100);
-  defaultMockMap.set('Float', () => Math.random * 200 - 100);
+  defaultMockMap.set('Int', () => Math.round(Math.random() * 200) - 100);
+  defaultMockMap.set('Float', () => Math.random() * 200 - 100);
   defaultMockMap.set('String', () => 'Hello World');
-  defaultMockMap.set('Boolean', () => Math.random > 0.5);
+  defaultMockMap.set('Boolean', () => Math.random() > 0.5);
   defaultMockMap.set('ID', () => uuid.v4());
 
   function mergeObjects(a, b) {