подумай сам(To "do the math" means to figure out or put together the information for yourself to come to a logical conclusion. Tumatutuma); сам прикинь(used for telling someone that when they consider all the facts and figures, something cannot succeed or be possible Баян); сам сделай вывод(The idiom "do the math" is widely understood in contemporary English to mean performing a calculation or reasoning logically to arrive at a conclusion, often implying that the solution is obvious. Баян); подсчитывать(You start doing the math, you get to 1% instead of 3%.ART Vancouver); подсчитать(diyaroschuk); поразмыслить(She didn’t need anyone to explain it—she just sat quietly and did the math, concluding that moving abroad would be the best option for her career. Source: theidioms.com'More)