Chapter 12: Racing Seconds

A 100-metre runner finishes in just 10 seconds. A meal cooks in 20 minutes. A train ride takes 6 hours. Time has many sizes , seconds, minutes, hours, days. Each one helps us in a different situation.

In this chapter we learn to read clocks, convert between time units, add and subtract time, and read the 24-hour format used in railway and airline timetables. By the end, you will be a master of every clock.

What's inside

• Seconds, minutes, hours and their relations.
• Reading clocks , analog and digital.
• The 24-hour format.
• Time problems , duration and difference.

How to read this chapter

Read in order. Keep an analog clock or a digital watch nearby. The hands-on tasks involve timing yourself doing small things , they make time feel real.