The locations of the jacks in the "I Spy Extreme Challenger" book can vary depending on the edition and version of the book. I recommend carefully scanning each page to find the jacks hidden within the intricate illustrations. You may need to examine details closely and consider different perspectives to locate them all.
One is on a pencil!
57
It is on the camel stamp on the left page
The ace in the "You Spy Extreme Challenger" game is located under the magnifying glass on the right side of the card. It is hidden within the design of the magnifying glass.
Behind the Christmas tree
In the bottom left corner on top of the musical scale and the scissors.
In the Spy Extreme Challenger game, the lunchbox can be found in the living room cabinet. It is hidden behind the blue vase on the middle shelf.
They are the hotdog buns on the two forks in the middle of the page.
Theres a mouse trap with a spring on Page 25.
I think it is on the side of the can on the bottom right hand page.
The snail is right by Harry's Test. It's the shell next to it.
On page 16 of I Spy Extreme Challenger, the bell is located on the bottom left corner. On page 17, the bell is on the bottom right corner.