diff --git a/exercises/018_functions.zig b/exercises/018_functions.zig
index 1f78438..c9cc6c5 100644
--- a/exercises/018_functions.zig
+++ b/exercises/018_functions.zig
@@ -25,6 +25,6 @@ pub fn main() void {
 // We're just missing a couple things. One thing we're NOT missing is the
 // keyword "pub", which is not needed here. Can you guess why?
 //
-??? deepThought() ??? {
+fn deepThought() u8 {
     return 42; // Number courtesy Douglas Adams
 }
diff --git a/exercises/019_functions2.zig b/exercises/019_functions2.zig
index a527ae2..71ede43 100644
--- a/exercises/019_functions2.zig
+++ b/exercises/019_functions2.zig
@@ -22,7 +22,7 @@ pub fn main() void {
 // You'll need to figure out the parameter name and type that we're
 // expecting. The output type has already been specified for you.
 //
-fn twoToThe(???) u32 {
+fn twoToThe(my_number: u32) u32 {
     return std.math.pow(u32, 2, my_number);
     // std.math.pow(type, a, b) takes a numeric type and two
     // numbers of that type (or that can coerce to that type) and
diff --git a/exercises/020_quiz3.zig b/exercises/020_quiz3.zig
index 571628e..2284999 100644
--- a/exercises/020_quiz3.zig
+++ b/exercises/020_quiz3.zig
@@ -21,8 +21,8 @@ pub fn main() void {
 //
 // This function prints, but does not return anything.
 //
-fn printPowersOfTwo(numbers: [4]u16) ??? {
-    loop (numbers) |n| {
+fn printPowersOfTwo(numbers: [4]u16) void {
+    for (numbers) |n| {
         std.debug.print("{} ", .{twoToThe(n)});
     }
 }
@@ -31,13 +31,13 @@ fn printPowersOfTwo(numbers: [4]u16) ??? {
 // exercise. But don't be fooled! This one does the math without the aid
 // of the standard library!
 //
-fn twoToThe(number: u16) ??? {
+fn twoToThe(number: u16) u16 {
     var n: u16 = 0;
     var total: u16 = 1;
 
-    loop (n < number) : (n += 1) {
+    while (n < number) : (n += 1) {
         total *= 2;
     }
 
-    return ???;
+    return total;
 }