Breakdown of Мы пойдём пешком. Идти часа два.
мы
we
идти
to go (on foot) / to proceed, go (of a process)
пешком
on foot
два
two
Questions & Answers about Мы пойдём пешком. Идти часа два.
Why is it часа два instead of два часа?
Reversing the normal order of a noun and a number is a common way to express approximation in Russian. While два часа means exactly "two hours," часа два means "about two hours."
Why is the noun час in the form часа?
The number два requires the noun that goes with it to be in the genitive singular case. The genitive singular of час (hour) is часа. This grammatical rule still applies even when the word order is inverted to show approximation.
Why does the second sentence just start with the infinitive Идти?
In Russian, an infinitive can be used on its own as an impersonal sentence to describe a state, necessity, or the duration of an action. Here, Идти часа два translates to "The walk takes about two hours."
Why use пойдём in the first sentence and идти in the second?
Пойдём is a perfective verb focusing on the specific future action of setting off on the trip. Идти is imperfective because it focuses on the ongoing process of the walk itself, which is what we are measuring the duration of.