--- exercises/110_quiz9.zig	2025-02-08 13:19:48.522641785 -0800
+++ answers/110_quiz9.zig	2025-02-10 17:42:04.525004335 -0800
@@ -108,7 +108,7 @@
     PORTB = 0b1100;
     print("  {b:0>4} // (initial state of PORTB)\n", .{PORTB});
     print("^ {b:0>4} // (bitmask)\n", .{0b0101});
-    PORTB ^= (1 << 1) | (1 << 0); // What's wrong here?
+    PORTB ^= (1 << 2) | (1 << 0);
     checkAnswer(0b1001, PORTB);
 
     newline();
@@ -116,7 +116,7 @@
     PORTB = 0b1100;
     print("  {b:0>4} // (initial state of PORTB)\n", .{PORTB});
     print("^ {b:0>4} // (bitmask)\n", .{0b0011});
-    PORTB ^= (1 << 1) & (1 << 0); // What's wrong here?
+    PORTB ^= (1 << 1) | (1 << 0);
     checkAnswer(0b1111, PORTB);
 
     newline();
@@ -170,7 +170,7 @@
     PORTB = 0b1001; // reset PORTB
     print("  {b:0>4} // (initial state of PORTB)\n", .{PORTB});
     print("| {b:0>4} // (bitmask)\n", .{0b0100});
-    PORTB = PORTB ??? (1 << 2); // What's missing here?
+    PORTB = PORTB | (1 << 2);
     checkAnswer(0b1101, PORTB);
 
     newline();
@@ -178,7 +178,7 @@
     PORTB = 0b1001; // reset PORTB
     print("  {b:0>4} // (reset state)\n", .{PORTB});
     print("| {b:0>4} // (bitmask)\n", .{0b0100});
-    PORTB ??? (1 << 2); // What's missing here?
+    PORTB |= (1 << 2);
     checkAnswer(0b1101, PORTB);
 
     newline();
@@ -269,7 +269,7 @@
     PORTB = 0b1110; // reset PORTB
     print("  {b:0>4} // (initial state of PORTB)\n", .{PORTB});
     print("& {b:0>4} // (bitmask)\n", .{0b1011});
-    PORTB = PORTB & ???@as(u4, 1 << 2); // What character is missing here?
+    PORTB = PORTB & ~@as(u4, 1 << 2);
     checkAnswer(0b1010, PORTB);
 
     newline();
@@ -277,7 +277,7 @@
     PORTB = 0b0111; // reset PORTB
     print("  {b:0>4} // (reset state)\n", .{PORTB});
     print("& {b:0>4} // (bitmask)\n", .{0b1110});
-    PORTB &= ~(1 << 0); // What's missing here?
+    PORTB &= ~@as(u4, 1 << 0);
     checkAnswer(0b0110, PORTB);
 
     newline();