NCERT Solutions for Class 5th Maths Chapter 12 Racing Seconds

About this chapter

A second is a very small piece of time. Say one thousand one out loud — that takes about one second. Blinking your eyes takes less than a second. The thin red hand on a wall clock is the seconds hand . It is the fastest hand: it goes right round the dial in one minute. 60 seconds make 1 minute. 60 minutes make 1 hour. This is the one fact the whole chapter rests on. Watch the seconds hand: after it has ticked 60 little marks it has gone once round, and the minute hand has moved on by exactly one mark. So 1 min = 60 s and 1 hr = 60 min . Time is counted in sixties, not in tens. In money, 10 tens make 100. In time, it is 60 that makes the next unit. So when seconds add up past 60, we carry 1 to the minutes. 40 s + 35 s = 75 s = 1 min 15 s. And when we cannot subtract, we borrow 1 minute and

• Raghav's yoga clocks, time elapsed, and the painting table
• hour format and 24-hour format
• Seconds
• Seconds or minutes? Tick the right cell
• Your own list, and how many you can do in a minute
• Three things to measure with a seconds hand
• Observe the clocks and fill in the blanks
• Add the red hand to the clock on the right
• (c) Minutes and seconds on a double number line
• Adding up times, and finding how long a journey took