"Two and two are four
four and four are eight
eight and eight are sixteen
sixteen and sixteen are thirty-two". I have a super-early memory of this being sung over my crib or bed.

Also, a song with many parts that I've never found anyone else to sing with:

"crank chisel, chisel,
crank chisel, chisel"

with

"whoop, whoop WHOOP,
whoop, whoop WHOOP"

and various other parts, sung together.

Dani