Left and Instr functions together?

I am trying to check if a cell contains the number "10" and return a 1 or a 0 in the next cell, but only if "10" is the first 2 numbers.
This is so I can find dates from October in my September sheet and mark them with a 1, but so far it is marking any cells that contain the number "10" (so the 10th day of the month as well as the 10th month.)

Currently I have this:

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Is there a way to use the Left function inside of the Instr function so it checks if the number 10 is in the first 2 numbers of a cell?

You're a genius! Thanks so much.