A couple of days ago, вечером (in the evening), I sat down с фотоальбомом (with a photo album) in my hands. I love looking through old pictures, especially those снятые моими родителями (taken by my parents). For some reason I have lots of photos from when I was младенцем (a baby) and then again, в первом классе (in the first grade). The pictures got me thinking about who I wanted to be when I was little. Together с моей лучшей подругой (with my best friend) we often dreamed of becoming either знаменитыми актрисами ( famous actresses) or учителями (teachers). We thought we’d make excellent teachers since would not load our students with домашней работой (homework).

Why am I telling you all this? Mostly because every single Russian noun you see in the above paragraph is in instrumental case. And every one of these nouns is an example of different instances in which instrumental case should be used.

Let’s quickly review them all, starting with the last one, домашней работой (homework). Here I use instrumental case to explain the instrument which will be used to carry out a particular action, the verb “to load”.

Учительница загрузила нас домашней работой (Teacher loaded us with homework)
Я мою пол шваброй – I am cleaning the floor with a mop – a mop is a tool I use for cleaning
Мальчик ковырял в носу пальцем – A boy picked his nose with his finger – a finger is an instrument the boy uses for picking his nose
Чеширский кот знаменит своей улыбкой, а Кот в шляпе – своей шляпой (Cheshire cat is famous for his smile, while Cat in the Hat – for his hat) – a smile and a hat are both instruments by which the cats get their fame.
Умом Россию не понять – Russia cannot be understood by mind alone – mind alone is not a sufficient instrument for understanding

Oftentimes you will hear something like this:
Я работаю продавцом в магазине бытовых приборов – I work as a sales person at an appliances store.
Когда я встретил мою жену, она работала танцовщицей в клубе – When I met my wife, she worked as a dancer at a club.
Сейчас я – домохозяйка, а раньше работала медсестрой – Now I am a housewife, but I used to work as a nurse.

Here, instrumental case is used for the noun продавец (sales person). Of course, were I simply state Я – продавец (I am a sales person), no instrumental case would be needed. However, since I am using the verb работать (to work) in the example above, putting my occupation in instrumental case becomes a must. Think of your occupation as a tool, an instrument with which you work.

Instrumental case is also used when we talk about a change of status. For example, when children talk about кем они хотят быть, когда вырастут (who they want to be when they grow up), they use instrumental case:

Когда я вырасту, я буду космонавтом – When I grow up, I will be a cosmonaut
Я ещё не решила, кем буду – балериной или ветеринаром – I haven’t decided yet who I am going to be, a ballerina or a veterinarian.
Когда я был маленьким [ребёнком], я боялся темноты – When I was little, I was afraid of the dark. Most of the time the noun ребёнком (child) is omitted, but implied.
Когда я буду взрослым, у меня будет много денег – When I will be a grown-up, I will have lots of money.

Adults use the “change of status” instrumental case a lot too:

Если ты не возьмёшся за ум, то ты станешь не космонавтом, а дворником – If you don’t get your act together, you will be a street-sweeper, not a cosmonaut.
Он стал завсегдатаем этого заведения – He became a regular at this establishment
Я проснулся с головной болью и на работу пришёл совсем больным – I woke up with a headache and came to work totally sick. (here больным is instrumental of больной, a sick person).

You will also need instrumental case when you are asking for or offering something with something else:

чай с сахаром – tea with sugar
бутерброд с колбасой – sandwich with lunch meat
фига с маслом – “fig with butter” – a whole lot of nothing or a big nothing

Similarly, if talking about people, you would say:

я с друзьями пошёл в кино – my friends and I went to the movies
Паша с Машей ел кашу – Pasha and Masha ate kasha
мы с подругой играли в классики – my friend and I played hopscotch
в кабинет зашёл начальник с замом – the boss and his deputy walked into the office

Perhaps confusingly, instrumental case is also used when talking about a time when action occurs:

Я схожу на почту утром – I will go to the post office in the morning. Here, instrumental case is used to explain when the action takes place – утром (in the morning).
Вечерами они пили пиво и обсуждали новости – Evenings they spent nursing beer and discussing the news. Now, let’s crank up the instrumental case in this sentence: Вечерами , c пивом в руках, они обменивались новостями (In the evenings, with beer in their hands, they exchanged news).

This post, написанный мной (written by me), would be incomplete, if I didn’t mention the use of instrumental case with the passive voice:

Что написано пером, не вырубить топором – What is written with a pen cannot be chopped with an ax.
Ветром намело глубокие сугробы – Deep snow banks were swept up by the wind
Температуру сбили только этим лекарством – Temperature was lowered only with this medicine.
Фотография была снята моим лучшим другом – A picture was taken by my best friend.

And that’s really all there is to the instrumental case. And now, it’s time to practice:

Кем вы хотели быть, когда были ребёнком? – Who did you want to be as a child?
Кем вы работаете сейчас? – What is your job?
Что вы делаете утром? – What do you do in the morning?
С чем вы едите блинчики? А бутерброды? – What do you eat pancakes with? What about sandwiches?
Кем написана ваша любимая книга? – Who wrote your favorite book?

If you comment with your answers, I will make sure to respond with corrections, explanations and words of encouragement.