diff --git a/lua/src/p0008.lua b/lua/src/p0008.lua
index b7f9f846..d150bdee 100644
--- a/lua/src/p0008.lua
+++ b/lua/src/p0008.lua
@@ -53,7 +53,7 @@ return {
                   .. "71636269561882670428252483600823257530420752963450")
         local answer = 0
 
-        for i = 1,(string.len(str)-13),1
+        for i = 1,(#str-13),1
         do
             local product = 1
             for j = i,(i+12),1
diff --git a/lua/src/p0034.lua b/lua/src/p0034.lua
index a6c53812..ef5f2444 100644
--- a/lua/src/p0034.lua
+++ b/lua/src/p0034.lua
@@ -23,7 +23,7 @@ return {
         do
             local xs = tostring(x)
             local sum = 0
-            for i = 1,string.len(xs),1
+            for i = 1,#xs,1
             do
                 sum = sum + factorial(tonumber(xs:sub(i, i)))
             end