Your English: Phrasal verbs: round

‘A spokesman for the organizing committee of the Olympic Games rounded on its many critics in the press after allegations that the private company responsible for the security arrangements was not up to the job.’ If you round on someone, you react angrily towards them, especially if they have criticized you. 

To round off means to end something in a satisfactory way, as in ‘Simpson rounded things off with a glorious goal minutes from the end’ or ‘They rounded off a wonderful evening by singing three of their best-known songs as an encore’.

If you round down a number, you reduce it to the nearest whole number of the nearest number ending in zero, as in ‘The total came to £10.04 but she rounded it down to £10’. Similarly, you can round a number up by increasing it to the nearest whole number ending in zero, as in ‘They rounded up the figure from 0.3871 to 0.39’.

Round up can also mean to find and arrest a number of people. as in ‘Dozens of political activists have been rounded up for questioning’ or ‘Police have orders to round up the troublemakers’. It is also used to mean to bring animals or people together in one place for a particular purpose, as in ‘I always used to help round up the cows at milking time’ or ‘Round the rest of the kids up and we’ll go back indoors’.

Used as a noun, a round-up is a summary of something, especially the most important parts of the news, as in ‘Now let’s get a round-up of the day’s sport’.