ARTHUR Season 10 Scavenger Hunt

As an inside-joke, every episode of Season 10 included the number 10 somewhere.

Happy Anniversary

 * Jane and David Read are celebrating their tenth anniversary
 * The Ten Spot Diner
 * The jukebox costs a dime (10 cents) to operate
 * The Bionic Bunny show is airing a 10th anniversary special where Bionic Bunny meets Dark Bunny

The Squirrels

 * One of the kid videos is "Silly Squirrels Count to 10"

Fern & Persimmony Glitchet

 * On top of Fern's door when she looks in the mailbox

Flaw and Order

 * A 10 is on the man hole cover

Arthur Changes Gears

 * On The Ghost of Bicycles Never Ridden's shirt

Unfinished

 * On the blimp.
 * On the floor where the blimp took off.
 * On the light lamp on the way to the place where the blimp took off.

Binky vs. Binky

 * Binky writes that he is 10 years old on the sign-up sheet

Operation D.W.

 * On Buster's transforming car/boat

Do You Speak George?

 * At the very end of the episode a streak in the dirt is the 1 and the marble arena is a 0.

World Girls

 * A 10% poster on the wall when Sue Ellen gets in the line
 * An Olympics World Girl doll scored a perfect 10
 * Bailey says they have 10 countries left to visit
 * On one of the doll assembly machines

Buster's Special Delivery

 * On the mailman's hat when Buster speaks to him.