feat: completed calculator using PEMDAS

Author: XavierCruz5106

lesson_06/expression/src/expression_calculator.ts

@@ -2,7 +2,24 @@ export class ExpressionCalculator {
   /** Returns the calculation of ((a + b) * c) / d^e */
   calculate(a: number, b: number, c: number, d: number, e: number): number {
     // Implement your code here to return the correct value.
-    return 0;
+    const sum = this.add(a, b);
+    const product = this.multiply(sum, c);
+    const power = this.pow(d, e);
+    const quotiant = this.divide(product, power);
+
+    return quotiant;
+  }
+
+  add(a: number, b: number): number {
+    return a + b;
+  }
+
+  divide(a: number, b: number): number {
+    return a / b;
+  }
+
+  multiply(a: number, b: number): number {
+    return a * b;
   }
 
   pow(base: number, exponent: number): number {