[Avodah] basic parsha question from Chaya Sarah -- Yishmael's age

[Isaac Balbin via Avodah]

> Much ado is made of Sarah's age as described in Torah (100 years and 
> 20 years and 7 years).  But at the end of the parsha, the same syntax 
> is used for Avraham and for Yishmael (100 years and 30 years and 5 
> years).  I *did* see meforshim explain why his age is mentioned at 
> all, but I didn't see why it used "shana" three times, like it says for Sarah.
> 
> Thoughts anyone?
> 
> — Sholom


Look carefully. Meas Shonoh is used. See Sefer Hazikaron on Pirush Rashi