diff --git a/src/main/scala/millfork/compiler/ExpressionCompiler.scala b/src/main/scala/millfork/compiler/ExpressionCompiler.scala
index 31324cd8..40391462 100644
--- a/src/main/scala/millfork/compiler/ExpressionCompiler.scala
+++ b/src/main/scala/millfork/compiler/ExpressionCompiler.scala
@@ -745,7 +745,7 @@ object ExpressionCompiler {
                 if (neg) MathOperator.DecimalMinus else MathOperator.DecimalPlus
               } else {
                 if (neg) MathOperator.Minus else MathOperator.Plus
-              }, c, v)
+              }, c, v).quickSimplify
             }
           exprTypeAndVariable.map(x => compileConstant(ctx, value.quickSimplify, x._2)).getOrElse(Nil)
         } else {
diff --git a/src/main/scala/millfork/env/Constant.scala b/src/main/scala/millfork/env/Constant.scala
index d15c02f2..11fcad5d 100644
--- a/src/main/scala/millfork/env/Constant.scala
+++ b/src/main/scala/millfork/env/Constant.scala
@@ -170,6 +170,22 @@ case class CompoundConstant(operator: MathOperator.Value, lhs: Constant, rhs: Co
     val l = lhs.quickSimplify
     val r = rhs.quickSimplify
     (l, r) match {
+      case (CompoundConstant(MathOperator.Plus, a, ll@NumericConstant(lv, _)), rr@NumericConstant(rv,_)) if operator == MathOperator.Plus =>
+        CompoundConstant(MathOperator.Plus, a, ll + rr).quickSimplify
+      case (CompoundConstant(MathOperator.Minus, a, ll@NumericConstant(lv, _)), rr@NumericConstant(rv,_)) if operator == MathOperator.Minus =>
+        CompoundConstant(MathOperator.Minus, a, ll + rr).quickSimplify
+      case (CompoundConstant(MathOperator.Plus, a, ll@NumericConstant(lv, _)), rr@NumericConstant(rv,_)) if operator == MathOperator.Minus =>
+        if (lv >= rv) {
+          CompoundConstant(MathOperator.Plus, a, ll - rr).quickSimplify
+        } else {
+          CompoundConstant(MathOperator.Minus, a, rr - ll).quickSimplify
+        }
+      case (CompoundConstant(MathOperator.Minus, a, ll@NumericConstant(lv, _)), rr@NumericConstant(rv,_)) if operator == MathOperator.Plus =>
+        if (lv >= rv) {
+          CompoundConstant(MathOperator.Minus, a, ll - rr).quickSimplify
+        } else {
+          CompoundConstant(MathOperator.Plus, a, rr - ll).quickSimplify
+        }
       case (CompoundConstant(MathOperator.Shl, HalfWordConstant(c1, true), NumericConstant(8, _)), HalfWordConstant(c2, false)) if operator == MathOperator.Or && c1 == c2 => c1
       case (NumericConstant(lv, ls), NumericConstant(rv, rs)) =>
         var size = ls max rs