Turns and minutes

In your book, Maths Mela (Chapter 3), we link the turns of the minute hand to minutes. The minute hand always turns clockwise, the way clock hands move. When it starts at 12 and goes all the way round, clockwise, back to 12, it has made a full turn, and 60 minutes have passed. So a full turn of the minute hand is 60 minutes.

Half of 60 minutes is 30 minutes, so in 30 minutes the minute hand makes a 1/2 turn: starting at 12, it ends pointing at 6. A quarter of 60 minutes is 15 minutes, so in 15 minutes it makes a 1/4 turn: from 12 to 3. In 45 minutes it makes three quarter turns, a 3/4 turn: from 12 to 9.

The clock face has 12 numbers, which split the full turn into 12 equal parts. Moving from one number to the next is a 1/12 turn. 60 minutes shared into 12 equal parts is 5 minutes each, so a 1/12 turn is 5 minutes: from 12 to 1.

Now we can find other turns. A 1/6 turn is two 1/12 turns (from 12 to 2), so it is 5 + 5 = 10 minutes. A 4/12 turn is four 1/12 turns (from 12 to 4), so it is 4 × 5 = 20 minutes.