Class 7 Maths Chapter 2 Exercise 2.5 Pdf Notes NCERT Solutions
Class 7 Maths Chapter 2 Fractions and Decimals Exercise 2.5 pdf notes:-
Exercise 2.5 Class 7 maths Chapter 2 Pdf Notes:-
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Ncert Solution for Class 6 Maths Chapter 2 Fractions and decimals Exercise 2.5 Tips:-
John has 15.50 and Salma has 15.75. Who has more money? To find this we need to compare the decimal numbers 15.50 and 15.75. To do this, we first compare the digits on the left of the decimal point, starting from the leftmost digit. Here both the digits 1 and 5, to the left of the decimal point, are same. So we compare the digits on the right of the decimal point starting from the tenths place. We find that 5 < 7, so we say 15.50 < 15.75. Thus, Salma has more money than John. If the digits at the tenths place are also same then compare the digits at the hundredths place and so on. Now compare quickly, 35.63 and 35.67; 20.1 and 20.01; 19.36 and 29.36. While converting lower units of money, length and weight, to their higher units, we are required to use decimals. For example, 3 paise = 3 100 = 0.03, 5g = 5 1000 kg = 0.005 kg, 7 cm = 0.07 m. Write 75 paise = ______, 250 g = _____ kg, 85 cm = _____m. We also know how to add and subtract decimals. Thus, 21.36 + 37.35 is
bserve the shift of the decimal point of the products in the table. Here the numbers are
multiplied by 10,100 and 1000. In 1.76 × 10 = 17.6, the digits are same i.e., 1, 7 and 6. Do
you observe this in other products also? Observe 1.76 and 17.6. To which side has the
decimal point shifted, right or left? The decimal point has shifted to the right by one place.
Note that 10 has one zero over 1.
In 1.76×100 = 176.0, observe 1.76 and 176.0. To which side and by how many
digits has the decimal point shifted? The decimal point has shifted to the right by two
places.
Note that 100 has two zeros over one.
Do you observe similar shifting of decimal point in other products also?
So we say, when a decimal number is multiplied by 10, 100 or 1000, the digits in
the product are same as in the decimal number but the decimal
point in the product is shifted to the right by as, many of places as
there are zeros over one.
Based on these observations we can now say
0.07 × 10 = 0.7, 0.07 × 100 = 7 and 0.07 × 1000 = 70.
Can you now tell 2.97 × 10 = ? 2.97 × 100 = ? 2.97 × 1000 = ?
Can you now help Reshma to find the total amount i.e., 8.50 × 150, that she has
to pay?
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