Manasara 6.27

6.27

madhye caikāṅgulaṃ proktaṃ paṅktyante dvyaṅgulaṃ tyajet
mithune prathamadaśake divase tvaṅgulaṃ tyajet

in the middle, one digit is declared; at the end of the ten-day period, he should discard two digits; / in Gemini, in the first ten days, he should discard [two] digits;