diff --git a/src/calculator.spec.ts b/src/calculator.spec.ts
new file mode 100644
index 0000000..f8dede2
--- /dev/null
+++ b/src/calculator.spec.ts
@@ -0,0 +1,51 @@
+import Calculator from "./calculator";
+
+describe('Calulator: no starting value', () => {
+  let calc
+  beforeEach(() => {
+    calc = new Calculator();
+  })
+
+  it('returns a value', () => {
+    expect(calc.total).toEqual(0);
+  })
+
+
+  it('calculator defaults to graphing mode', () => {
+    expect(calc.mode).toEqual("graphing");
+  })
+
+  it('can perform addition', () => {
+    calc.plus(3)
+    expect(calc.total).toEqual(3);
+    calc.plus(7)
+    expect(calc.total).toEqual(10);
+    calc.plus(3)
+    expect(calc.total).toEqual(13);
+  })
+
+  // it('can perform subtraction', () => {
+  //   calc.minus(1)
+  //   expect(calc.total).toEqual(-1);
+  //   calc.minus(2)
+  //   expect(calc.total).toEqual(-3);
+  //   calc.minus(3)
+  //   expect(calc.total).toEqual(-6);
+  // })
+});
+
+describe('Calulator: starting value 99', () => {
+  let calc
+  beforeEach(() => {
+    calc = new Calculator();
+  })
+
+  it('returns a value', () => {
+    expect(calc.total).toEqual(0);
+  })
+
+  it('can zero out the internal value', () => {
+    calc.c()
+    expect(calc.total).toEqual(0);
+  })
+});
diff --git a/src/calculator.ts b/src/calculator.ts
new file mode 100644
index 0000000..420213b
--- /dev/null
+++ b/src/calculator.ts
@@ -0,0 +1,45 @@
+export default class Calculator {
+  private value = 0;
+  private calcMode = ""
+  constructor(scientificMode = false, value = 0) {
+    this.value = value
+
+    if(scientificMode) {
+      this.calcMode = "science!"
+    } else if(scientificMode && this.value > 0) {
+      this.calcMode = "I dont know I'm just making a branching statement"
+    } else {
+      this.calcMode = "graphing"
+    }
+  }
+
+  get total() {
+    return this.value
+  }
+
+  get mode() {
+    return this.calcMode
+  }
+
+  plus = (num) => {
+    this.value = this.value + num
+    return this.total
+  }
+
+  minus = (num) => {
+    this.value = this.value - num
+    return this.total
+  }
+
+
+  multiply = (num) => {
+    this.value = this.value * num
+    return this.total
+  }
+
+  c = () => {
+    this.value = 0
+    return this.total
+  }
+  
+}