diff --git a/projects/advent-of-code/src/year2020/Solutions.kiss b/projects/advent-of-code/src/year2020/Solutions.kiss
index 75b08cc1..c4e4f205 100644
--- a/projects/advent-of-code/src/year2020/Solutions.kiss
+++ b/projects/advent-of-code/src/year2020/Solutions.kiss
@@ -30,9 +30,8 @@
     (deflocal :Map<Int,Int> numbersMap (new Map))
     (deflocal &mut pair null)
     (doFor number numbers
-        // TODO implement dict-set, dict-get, set-nth, and use them
-        (set (nth numbersMap number) (- sum number))
-        (let [requiredForPair (nth numbersMap number)]
+        (dict-set numbersMap number (- sum number))
+        (let [requiredForPair (dict-get numbersMap number)]
             (when (numbersMap.exists requiredForPair)
                 (set pair (or pair [number requiredForPair])))))
         
diff --git a/src/kiss/Macros.hx b/src/kiss/Macros.hx
index 13abe2de..80dab6ee 100644
--- a/src/kiss/Macros.hx
+++ b/src/kiss/Macros.hx
@@ -100,6 +100,21 @@ class Macros {
             ]).withPosOf(wholeExp);
         };
 
+        function arraySet(wholeExp:ReaderExp, exps:Array<ReaderExp>, k:KissState) {
+            return CallExp(Symbol("set").withPosOf(wholeExp), [
+                CallExp(Symbol("nth").withPosOf(wholeExp), [exps[0], exps[1]]).withPosOf(wholeExp),
+                exps[2]
+            ]).withPosOf(wholeExp);
+        }
+        macros["set-nth"] = (wholeExp:ReaderExp, exps:Array<ReaderExp>, k:KissState) -> {
+            wholeExp.checkNumArgs(3, 3, "(set-nth [list] [index] [value])");
+            arraySet(wholeExp, exps, k);
+        };
+        macros["dict-set"] = (wholeExp:ReaderExp, exps:Array<ReaderExp>, k:KissState) -> {
+            wholeExp.checkNumArgs(3, 3, "(dict-set [dict] [key] [value])");
+            arraySet(wholeExp, exps, k);
+        };
+
         // Under the hood, (defmacrofun ...) defines a runtime function that accepts Quote arguments and a special form that quotes the arguments to macrofun calls
         macros["defmacrofun"] = (wholeExp:ReaderExp, exps:Array<ReaderExp>, k:KissState) -> {
             wholeExp.checkNumArgs(3, null, "(defmacrofun [name] [args] [body...])");
diff --git a/src/kiss/SpecialForms.hx b/src/kiss/SpecialForms.hx
index d78fe557..155f4a01 100644
--- a/src/kiss/SpecialForms.hx
+++ b/src/kiss/SpecialForms.hx
@@ -25,9 +25,16 @@ class SpecialForms {
             EBlock([for (bodyExp in args) k.convert(bodyExp)]).withMacroPosOf(wholeExp);
         };
 
+        function arrayAccess(wholeExp:ReaderExp, args:Array<ReaderExp>, k:KissState) {
+            return EArray(k.convert(args[0]), k.convert(args[1])).withMacroPosOf(wholeExp);
+        };
         map["nth"] = (wholeExp:ReaderExp, args:Array<ReaderExp>, k:KissState) -> {
             wholeExp.checkNumArgs(2, 2, "(nth [list] [idx])");
-            EArray(k.convert(args[0]), k.convert(args[1])).withMacroPosOf(wholeExp);
+            arrayAccess(wholeExp, args, k);
+        };
+        map["dict-get"] = (wholeExp:ReaderExp, args:Array<ReaderExp>, k:KissState) -> {
+            wholeExp.checkNumArgs(2, 2, "(dict-get [dict] [key])");
+            arrayAccess(wholeExp, args, k);
         };
 
         function makeQuickNth(idx:Int, name:String) {