Done

index.js

@@ -0,0 +1,49 @@
+function add(a = 1, b = 80) {
+  return (a + b)}
+
+function subtract(a = 60, b = 40) {
+  return (a-b)}
+
+function multiply(a = 2, b = 3.4) {
+  return (a*b)}
+
+function divide(a = 5, b = 2.5) {
+  return (a/b)}
+
+var number = 10
+function add5() {
+  number += 5
+}
+
+function divideBy3() {
+  number /= 3
+}
+
+divideBy3()
+console.log(number)
+add5()
+console.log(number)
+
+number = 10
+add5()
+console.log(number)
+divideBy3 ()
+console.log(number)
+
+function increment(number) {
+  return number += 1
+}
+
+function decrement(number) {
+  return number -= 1
+}
+
+function makeInt(number) {
+  return parseInt (number, 10)
+}
+
+function preserveDecimal(number) {
+  return parseFloat (number)
+}
+
+