Adding main operations

Implement add/subtrc/multiply/divide. Also add function operate which takes 2 operand and operator and then call callback operation function

script.js

@@ -0,0 +1,25 @@
+let operator;
+let firstOperand;
+let secondOperand;
+
+function add(a, b) {
+  return a + b;
+}
+
+function subtract(a, b) {
+  return a - b;
+}
+
+function multiply(a, b) {
+  return a * b;
+}
+
+function divide(a, b) {
+  return a / b;
+}
+
+function operate(operator, leftNum, rightNum) {
+  return operator(leftNum, rightNum);
+}
+
+console.log(operate(subtract, 5, 2));