I was conversing with my Japanese colleague:
Me: Do you know how much a melon costs in my home country?
Colleague: I do not know.
Me: Take a guess.
I asked him how to say take a guess
. He first told me to use 推測{すいそく}してみる
, but later retracted and told me to use あててみる
. Which one is more natural in day to day conversation?