թ. two by two, in twos.

1) binary,binomial,dyadic
2) 1,2,3,4,5,6,7,8,9,0,one,two,three,four,five,six,seven,eight,nine,zero,ten,eleven,twelve,thirteen,fourteen,fifteen,sixteen,seventeen,eighteen,nineteen,twenty,thirty,forty,fifty,sixty,seventy,eighty,ninety,hundred,thousand,million,milliard,billion