         expected = @exp_builder(open_expression: {open_expression: [8]})
         expect(exp).toBeAnEqualExpressionTo expected
 
-    describe "when the manipulation to be manipulated has an exponentiation as its last element", ->
+    describe "when the equation has as its last element an exponentiation ", ->
       describe "with no power", ->
         beforeEach ->
-          @exp = @exp_builder('^': [10, null])
+          @exp = @exp_builder('^': [10, {open_expression:  null}])
 
         it "inserts the number into the exponentiation", ->
           new_exp = @manip.append_number.build(value: 11).invoke(@exp)
-
           expected = @exp_builder('^': [10, {open_expression: 11}])
           expect(new_exp).toBeAnEqualExpressionTo expected
 

          expected = @exp_builder({'^': [10,11]}, '*', 12)
          expect(new_exp).toBeAnEqualExpressionTo expected


  describe "opening a new sub expression", ->
    it "adds a sub-expression to the expression", ->

      exp = @exp_builder(1)
      new_exp = @manip.append_multiplication.build().invoke(exp)
      expect(new_exp.last() instanceof @math.components.multiplication).toEqual true

    it "correctly adds multiplication to an exponentiation", ->
      exp = @exp_builder('^': [1, 2])
      new_exp = @manip.append_multiplication.build().invoke(exp)
      expected = @exp_builder({'^': [1, 2]}, '*')
      expect(new_exp).toBeAnEqualExpressionTo expected

    it_inserts_component_into_the_last_nested_open_expression(
      name: 'multiplication'
