diff --git a/flang/lib/Evaluate/fold-matmul.h b/flang/lib/Evaluate/fold-matmul.h
index be9c547d45286..c3d65a9040909 100644
--- a/flang/lib/Evaluate/fold-matmul.h
+++ b/flang/lib/Evaluate/fold-matmul.h
@@ -61,7 +61,7 @@ static Expr<T> FoldMatmul(FoldingContext &context, FunctionRef<T> &&funcRef) {
           auto product{aElt.Multiply(bElt)};
           overflow |= product.flags.test(RealFlag::Overflow);
           if constexpr (useKahanSummation) {
-            auto next{correction.Add(product.value, rounding)};
+            auto next{product.value.Subtract(correction, rounding)};
             overflow |= next.flags.test(RealFlag::Overflow);
             auto added{sum.Add(next.value, rounding)};
             overflow |= added.flags.test(RealFlag::Overflow);
diff --git a/flang/lib/Evaluate/fold-real.cpp b/flang/lib/Evaluate/fold-real.cpp
index 0b79a417942a4..6fb5249c8a5e2 100644
--- a/flang/lib/Evaluate/fold-real.cpp
+++ b/flang/lib/Evaluate/fold-real.cpp
@@ -78,7 +78,7 @@ template <int KIND> class Norm2Accumulator {
       auto scaled{item.Divide(scale).value};
       auto square{scaled.Multiply(scaled).value};
       if constexpr (useKahanSummation) {
-        auto next{square.Add(correction_, rounding_)};
+        auto next{square.Subtract(correction_, rounding_)};
         overflow_ |= next.flags.test(RealFlag::Overflow);
         auto sum{element.Add(next.value, rounding_)};
         overflow_ |= sum.flags.test(RealFlag::Overflow);
diff --git a/flang/lib/Evaluate/fold-reduction.h b/flang/lib/Evaluate/fold-reduction.h
index 8ca0794ab0fc7..b1b81d8740d3f 100644
--- a/flang/lib/Evaluate/fold-reduction.h
+++ b/flang/lib/Evaluate/fold-reduction.h
@@ -47,7 +47,7 @@ static Expr<T> FoldDotProduct(
       const auto &rounding{context.targetCharacteristics().roundingMode()};
       for (const Element &x : cProducts.values()) {
         if constexpr (useKahanSummation) {
-          auto next{correction.Add(x, rounding)};
+          auto next{x.Subtract(correction, rounding)};
           overflow |= next.flags.test(RealFlag::Overflow);
           auto added{sum.Add(next.value, rounding)};
           overflow |= added.flags.test(RealFlag::Overflow);
@@ -90,7 +90,7 @@ static Expr<T> FoldDotProduct(
       const auto &rounding{context.targetCharacteristics().roundingMode()};
       for (const Element &x : cProducts.values()) {
         if constexpr (useKahanSummation) {
-          auto next{correction.Add(x, rounding)};
+          auto next{x.Subtract(correction, rounding)};
           overflow |= next.flags.test(RealFlag::Overflow);
           auto added{sum.Add(next.value, rounding)};
           overflow |= added.flags.test(RealFlag::Overflow);
@@ -348,7 +348,7 @@ template <typename T> class SumAccumulator {
       overflow_ |= sum.overflow;
       element = sum.value;
     } else { // Real & Complex: use Kahan summation
-      auto next{array_.At(at).Add(correction_, rounding_)};
+      auto next{array_.At(at).Subtract(correction_, rounding_)};
       overflow_ |= next.flags.test(RealFlag::Overflow);
       auto sum{element.Add(next.value, rounding_)};
       overflow_ |= sum.flags.test(RealFlag::Overflow);
diff --git a/flang/runtime/sum.cpp b/flang/runtime/sum.cpp
index 04241443275eb..10b8124254652 100644
--- a/flang/runtime/sum.cpp
+++ b/flang/runtime/sum.cpp
@@ -53,7 +53,7 @@ template <typename INTERMEDIATE> class RealSumAccumulator {
   }
   template <typename A> RT_API_ATTRS bool Accumulate(A x) {
     // Kahan summation
-    auto next{x + correction_};
+    auto next{x - correction_};
     auto oldSum{sum_};
     sum_ += next;
     correction_ = (sum_ - oldSum) - next; // algebraically zero