diff --git a/rx/factory_test.go b/rx/factory_test.go
index e5078e3..3cf503e 100644
--- a/rx/factory_test.go
+++ b/rx/factory_test.go
@@ -719,7 +719,7 @@ var _ = Describe("Factory", func() {
 		})
 
 		When("given: custom structure", func() {
-			It("🧪 should:  ", func() {
+			It("🧪 should: create observable without error", func() {
 				// Test_Just_CustomStructure
 				defer leaktest.Check(GinkgoT())()
 
@@ -745,7 +745,7 @@ var _ = Describe("Factory", func() {
 		})
 
 		When("given: channel", func() {
-			XIt("🧪 should: ???", func() {
+			XIt("🧪 should: ???", decorators.Label("sending chan not supported yet"), func() {
 				// Test_Just_Channel
 				defer leaktest.Check(GinkgoT())()
 
@@ -1039,7 +1039,7 @@ var _ = Describe("Factory", func() {
 
 		Context("NominatedRangeIterator", func() {
 			When("positive count", func() {
-				It("🧪 should: create observable", decorators.Label("need pointer receiver on T"), func() {
+				It("🧪 should: create observable", func() {
 					// Test_Range
 					defer leaktest.Check(GinkgoT())()
 
diff --git a/rx/observable-operator-average_test.go b/rx/observable-operator-average_test.go
index ba6d952..95f8150 100644
--- a/rx/observable-operator-average_test.go
+++ b/rx/observable-operator-average_test.go
@@ -27,7 +27,6 @@ import (
 
 	"github.com/fortytw2/leaktest"
 	. "github.com/onsi/ginkgo/v2" //nolint:revive // ginkgo ok
-	"github.com/onsi/ginkgo/v2/dsl/decorators"
 
 	"github.com/snivilised/lorax/rx"
 )
@@ -146,8 +145,8 @@ var _ = Describe("Observable operator", func() {
 		})
 
 		Context("Parallel/Error", func() {
-			Context("given: foo", func() {
-				XIt("🧪 should: ", decorators.Label("broken average.gatherNext"), func() {
+			Context("given: invalid input", func() {
+				It("🧪 should: result in error", func() {
 					// rxgo: Test_Observable_AverageFloat32_Parallel_Error
 					defer leaktest.Check(GinkgoT())()
 
diff --git a/rx/observable-operator-reduce_test.go b/rx/observable-operator-reduce_test.go
index 643ef6c..5fa6d3b 100644
--- a/rx/observable-operator-reduce_test.go
+++ b/rx/observable-operator-reduce_test.go
@@ -27,13 +27,12 @@ import (
 
 	"github.com/fortytw2/leaktest"
 	. "github.com/onsi/ginkgo/v2" //nolint:revive // ginkgo ok
-	"github.com/onsi/ginkgo/v2/dsl/decorators"
 	"github.com/snivilised/lorax/enums"
 	"github.com/snivilised/lorax/rx"
 )
 
 var _ = Describe("Observable operator", func() {
-	XContext("Reduce", decorators.Label("broken by reduce acc"), func() {
+	Context("Reduce", func() {
 		When("using Range", func() {
 			It("🧪 should: compute reduction ok", func() {
 				// rxgo: Test_Observable_Reduce
@@ -45,9 +44,9 @@ var _ = Describe("Observable operator", func() {
 				obs := rx.Range(&rx.NumericRangeIterator[int]{
 					StartAt: 1,
 					Whilst:  rx.LessThan(10001),
-				}).Reduce( // 1, 10000
-					func(_ context.Context, acc, num rx.Item[int]) (int, error) {
-						return acc.V + num.Num(), nil
+				}).Reduce(
+					func(_ context.Context, acc, item rx.Item[int]) (int, error) {
+						return acc.V + item.V, nil
 					},
 				)
 				rx.Assert(ctx, obs,
@@ -104,7 +103,7 @@ var _ = Describe("Observable operator", func() {
 
 		Context("Parallel", func() {
 			When("using Range", func() {
-				XIt("🧪 should: compute reduction ok", decorators.Label("repairing"), func() {
+				It("🧪 should: compute reduction ok", func() {
 					// rxgo: Test_Observable_Reduce_Parallel
 					defer leaktest.Check(GinkgoT())()
 
@@ -113,10 +112,10 @@ var _ = Describe("Observable operator", func() {
 
 					obs := rx.Range(&rx.NumericRangeIterator[int]{
 						StartAt: 1,
-						Whilst:  rx.LessThan(6),
+						Whilst:  rx.LessThan(10001),
 					}).Reduce(
-						func(_ context.Context, acc, num rx.Item[int]) (int, error) {
-							return acc.Num() + num.Num(), nil
+						func(_ context.Context, acc, item rx.Item[int]) (int, error) {
+							return acc.V + item.V, nil
 						}, rx.WithCPUPool[int](),
 					)
 					rx.Assert(ctx, obs,
@@ -131,7 +130,7 @@ var _ = Describe("Observable operator", func() {
 
 		Context("Parallel/Error", func() {
 			When("using Range", func() {
-				XIt("🧪 should: result in error", func() {
+				It("🧪 should: result in error", func() {
 					// rxgo: Test_Observable_Reduce_Parallel_Error
 					defer leaktest.Check(GinkgoT())()
 
@@ -141,11 +140,11 @@ var _ = Describe("Observable operator", func() {
 						StartAt: 1,
 						Whilst:  rx.LessThan(10001),
 					}).Reduce(
-						func(_ context.Context, acc, num rx.Item[int]) (int, error) {
-							if num.Num() == 1000 {
+						func(_ context.Context, acc, item rx.Item[int]) (int, error) {
+							if item.V == 1000 {
 								return 0, errFoo
 							}
-							return acc.Num() + num.Num(), nil
+							return acc.V + item.V, nil
 						}, rx.WithContext[int](ctx), rx.WithCPUPool[int](),
 					)
 					rx.Assert(ctx, obs,
@@ -157,21 +156,22 @@ var _ = Describe("Observable operator", func() {
 			})
 
 			When("error with error strategy", func() {
-				XIt("🧪 should: result in error", func() {
+				It("🧪 should: result in error", func() {
 					// rxgo: Test_Observable_Reduce_Parallel_WithErrorStrategy
 					defer leaktest.Check(GinkgoT())()
 
 					ctx, cancel := context.WithCancel(context.Background())
 					defer cancel()
+
 					obs := rx.Range(&rx.NumericRangeIterator[int]{
 						StartAt: 1,
 						Whilst:  rx.LessThan(10001),
 					}).Reduce(
-						func(_ context.Context, acc, num rx.Item[int]) (int, error) {
-							if num.Num() == 1 {
+						func(_ context.Context, acc, item rx.Item[int]) (int, error) {
+							if item.V == 1 {
 								return 0, errFoo
 							}
-							return acc.Num() + num.Num(), nil
+							return acc.V + item.V, nil
 						}, rx.WithCPUPool[int](), rx.WithErrorStrategy[int](enums.ContinueOnError),
 					)
 					rx.Assert(ctx, obs,
diff --git a/rx/observable-operator-sum_test.go b/rx/observable-operator-sum_test.go
index 89dc035..e508b3a 100644
--- a/rx/observable-operator-sum_test.go
+++ b/rx/observable-operator-sum_test.go
@@ -27,7 +27,6 @@ import (
 
 	"github.com/fortytw2/leaktest"
 	. "github.com/onsi/ginkgo/v2" //nolint:revive // ginkgo ok
-	"github.com/onsi/ginkgo/v2/dsl/decorators"
 
 	"github.com/snivilised/lorax/rx"
 )
@@ -35,7 +34,7 @@ import (
 var _ = Describe("Observable operator", func() {
 	Context("Sum", func() {
 		When("principle", func() {
-			XIt("🧪 should: return sum", decorators.Label("broken by reduce acc"), func() {
+			It("🧪 should: return sum", func() {
 				// rxgo: Test_Observable_SumFloat32_OnlyFloat32
 				defer leaktest.Check(GinkgoT())()
 
diff --git a/rx/observable-operator.go b/rx/observable-operator.go
index 1d4af7b..dfaa5d7 100644
--- a/rx/observable-operator.go
+++ b/rx/observable-operator.go
@@ -93,6 +93,7 @@ func (op *allOperator[T]) gatherNext(ctx context.Context, item Item[T],
 	}
 }
 
+// Average calculates the average of numbers emitted by an Observable and emits the result.
 func (o *ObservableImpl[T]) Average(opts ...Option[T],
 ) Single[T] {
 	const (
@@ -1496,7 +1497,7 @@ func (o *ObservableImpl[T]) Reduce(apply Func2[T], opts ...Option[T]) OptionalSi
 	return optionalSingle(o.parent, o, func() operator[T] {
 		return &reduceOperator[T]{
 			apply: apply,
-			acc:   Num[T](0), // acc needs to be a Num: bomb!!!
+			acc:   Zero[T](),
 			empty: true,
 		}
 	}, forceSeq, bypassGather, opts...)
@@ -1512,7 +1513,7 @@ func (op *reduceOperator[T]) next(ctx context.Context, item Item[T],
 	dst chan<- Item[T], operatorOptions operatorOptions[T],
 ) {
 	op.empty = false
-	v, err := op.apply(ctx, op.acc, item) // bomb!!!
+	v, err := op.apply(ctx, op.acc, item)
 
 	if err != nil {
 		Error[T](err).SendContext(ctx, dst)
@@ -2233,10 +2234,9 @@ func (o *ObservableImpl[T]) StartWith(iterable Iterable[T], opts ...Option[T]) O
 
 // Sum calculates the average emitted by an Observable and emits the result
 func (o *ObservableImpl[T]) Sum(opts ...Option[T]) OptionalSingle[T] {
-	options := parseOptions[T]()
+	options := parseOptions(opts...)
 	calc := options.calc()
 
-	// TODO: bomb!!!: do we use Num?
 	return o.Reduce(func(_ context.Context, acc, item Item[T]) (T, error) {
 		if calc == nil {
 			var (