The number "1" printed on the top of your Cuisinart Compact 4-Slice Toaster CPT-142 likely indicates the designated toasting setting for the rightmost slot. Many toasters come with multiple slots and adjustable settings, allowing you to toast different types of bread or achieve your preferred level of toasting.
By labeling the slots with numbers, the toaster manufacturer helps users identify which slot corresponds to a specific toasting setting. For example, if you prefer a lighter toasting level for your bread in the rightmost slot, you can set it to "1" while setting the left slot to a different number or level to accommodate different preferences or types of bread.
Keep in mind that toaster models may vary, so it's always a good idea to refer to the user manual or instructions that came with your toaster for specific details about the settings and their corresponding numbers.