(i) 20 minutes into seconds
1 min = 60 seconds
Therefore 20 min = 60 \(\times\) 20 = 1200 seconds
(ii) 5 hours 35 minutes 40 seconds into seconds.
1 hour = 3600 seconds
5 hour = 5 \(\times\) 3600 = 18000 sec.
1 min = 60 see
35 min = 35 \(\times\) 60 = 2100 see
Therefore 5 hours 35 minutes 40 seconds
= (18000 + 2100 + 40) sec
= 20140 seconds
(iii) 3 1/2 hours into minutes
1 hour = 60 min
7 1/2 hours = 60 \(\times\) 7/2 = 210 minutes
(iv) 580 minutes into hours
60 min = 1 hour
580 min = 1/60 \(\times\) 580
= 58/6 = 9 4/6
= 9 hours 40 min (4 / 6 = 40 min)
(v) 25200 seconds into hours.
 3600 sec = 1 hour
25200 sec = 1 /3600 \(\times\) 25200 = 252 / 36 = 7 hours

Convert in the format : YYYY/MM/DD

Mala's age : 18 yrs 10 months 15 days

1km = 1000m
Maran Walks = 1.5 km
= 1.5 \(\times\)1000 = 1500m
Mahizhan walks = 1400m
Difference = 1500 - 1400 = 100m
Maran walks more distance and by 100m

Thenmozhi's height 1m 25 cm Therefore 1 student = 15ml of oil
= 125 cm 
She grows in 1year = 5 cm
Therefore 6 years = 5 \(\times\) 6 = 30 cm 
After 6 years, 
Thenmozhi's height = (125 + 30) cm needed.
= 155 cm

10 mm = 1 cm
100 cm = 1 m
1000 cm = 1 km
Therefore 10 mm = 1cm
i) 13000 mm = 1 / 10 \(\times\) 13000 = 1300 cm
100 cm = 1 m
1300 cm = 1 / 100 \(\times\) 1300 = 13 m
1000 m = 1 km
13 m = 1 / 1000 \(\times\) 13
= 0.013 km
= 13000 mm
= (0.013 km, 13m, 1300 cm)
(ii) 8257 ml (kl, I)
= 1000 ml = 1l
1000 l= 1 kl
1000 ml = 11
8257 ml = 1 / 1000 \(\times\) 8257
= 8.257 I
1000 1= 1 kl
8.257 I = 1 / 1000 \(\times\) 8.257
= 0.008257 kl
8257 ml (0.008257 kl, 8.257 I)