Class 6 - Mathematics
Chapter - Fractions and Decimals : Exercise 2.5
Top Block 1
Question : 1.Which is greater:
(i) 0.5 or 0.05
(ii) 0.7 or 0.5
(iii) 7 or 0.7
(iv) 1.37 or 1.49
(v) 2.03 or 2.30
(vi) 0.8 or 0.88
Answer :
(i) 0.5 > 0.05
(ii) 0.7 > 0.5
(iii) 7 > 0.7
(iv) 1.37 < 1.49
(v) 2.03 < 2.30
(vi) 0.8 < 0.88
Question : 2.Express as rupees using decimals:
(i) 7 paise
(ii) 7 rupees 7 paise
(iii) 77 rupees 77 paise
(iv) 50 paise
(v) 235 paise
Answer :
∵ 100 paise = Re. 1
∴ 1 paisa = Re. 1⁄100
7 paise = Re. 7⁄100 = Re. 0.07
7 rupees 7 paise = Rs. 7 + Re. 7⁄100 = Rs. 7 + Re. 0.07 = Rs. 7.07
77 rupees 77 paise = Rs. 77 + Re. 77⁄100 = Rs. 77 + Re. 0.77 = Rs. 77.77
50 paise = Re. 50⁄100 = Re. 0.50
235 paise = Re. 235⁄100= Rs. 2.35
Question : 3.
(i) Express 5 cm in metre and kilometer.
(ii) Express 35 mm in cm, m and km.
Answer :
(i) Express 5 cm in meter and kilometer.
∵ 100 cm = 1 meter
∴ 1 cm = 1⁄100 meter ⇒ 5 cm = 5⁄100 = 0.05 meter.
Now, ∵ 1000 meters = 1 kilometers
∴ 1 meter = 1⁄1000 kilometer
⇒ 0.05 meter = 0.05⁄1000 = 0.00005 kilometer
(ii) Express 35 mm in cm, m and km.
∵ 10 mm = 1 cm
∴ 1 mm = 1⁄10 cm ⇒ 35 mm = 35⁄103510 = 3.5 cm
Now, ∵ 100 cm = 1 meter
∴ 1 cm = 1⁄100 meter ⇒3.5 cm = 3.5⁄100 = 0.035 meter
Again, ∵ 1000 meters = 1 kilometers
∴ 1 meter = 1⁄1000 kilometer
⇒ 0.035 meter = 0.035⁄100 = 0.000035 kilometer
Question : 4.Express in kg.:
(i) 200 g
(ii) 3470 g
(iii)4 kg 8 g
Answer :
Les us consider , 1000 g = 1 kg ⇒ 1 g = 1⁄1000 kg
200 g = (200×1⁄1000 ) kg = 0.2 kg
3470 g = (3470×1⁄1000 ) kg = 3.470 kg
4 kg 8 g = 4 kg + (8×1⁄1000 ) kg = 4 kg + 0.008 kg = 4.008 kg
Question : 5.Write the following decimal numbers in the expanded form:
(i) 20.03
(ii) 2.03
(iii) 200.03
(iv) 2.034
Answer :
(i) 20.03 = 2 × 10 + 0 × 1 + 0 × 1⁄10 + 3×1⁄100
(ii) 2.03 = 2 × 1 + 0 × 1⁄10 + 3 × 1⁄100
(iii) 200.03 = 2 × 100 + 0 × 10 + 0 × 1 + 0 × 1⁄10 + 3 × 1⁄100
(iv) 2.034 = 2 × 1 + 0 × 1⁄10 + 3 × 1⁄100 + 4 × 1⁄1000
Question : 6.Write the place value of 2 in the following decimal numbers:
(i) 2.56
(ii) 21.37
(iii) 10.25
(iv) 9.42
(v) 63.352
Answer :
(i) Place value of 2 in 2.56 = 2 x 1 = 2 ones
(ii) Place value of 2 in 21.37 = 2 x 10 = 2 tens
(iii) Place value of 2 in 10.25 = 2× 1⁄10 = 2 tenths
(iv) Place value of 2 in 9.42 = 2 × 1⁄100 = 2 hundredth
(v) Place value of 2 in 63.352 = 2 × 1⁄1000 = 2 thousandth
Mddle block 1
Question : 7.Dinesh went from place A to place B and from there to place C. A is 7.5 km from B and B is 12.7 km from C. Ayub went from place A to place D and from there to place C. D is 9.3 km from A and C is 11.8 km from D. Who travelled more and by how much?
Answer :
Distance travelled by Dinesh when he went from place A to place B = 7.5 km and from place B to C = 12.7 km.
Total distance covered by Dinesh = AB + BC
= 7.5 + 12.7 = 20.2 km
Total distance covered by Ayub = AD + DC
= 9.3 + 11.8 = 21.1 km
On comparing the total distance of Ayub and Dinesh,
21.1 km > 20.2 km
Therefore, Ayub covered more distance by 21.1 – 20.2 = 0.9 km = 900 m
Question : 8.Shyam bought 5 kg 300 g apples and 3 kg 250 g mangoes. Sarala^ bought 4 kg 800 g oranges and 4 kg 150 g bananas. Who bought more fruits?
Answer :
Total weight of fruits bought by Shyam = 5 kg 300 g + 3 kg 250 g = 8 kg 550 g
Total weight of fruits bought by Sarala = 4 kg 800 g + 4 kg 150 g = 8 kg 950 g
On comparing the quantity of fruits,
8 kg 550 g < 8 kg 950 g
Therefore, Sarala bought more fruits.
Question : 9.How much less is 28 km than 42.6 km?
Answer :
We have to find the difference of 42.6 km and 28 km.
42.6 – 28.0 = 14.6 km
Therefore 14.6 km less is 28 km than 42.6 km.