You do realize that requires !10 of these small items just to map the information in our base 10 system. So that means 55 items. Then to write out the first 100 digits of pi would be 3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679, so let me take a second to add this all up.
That's 474 items, along with something to explain as decimals, and a place-holder to represent 0 items in something other than a lack of an example.
That's really complicated. I think what would be better would be to: Wave back, and then position yourself with your palms visible, in a non threatening position. If contact is possible, begin by pointing to yourself and saying "Human". This is our new name until we return home. Then gesture to the ETI for them to follow suit. Provide more examples as needed.