NCERT Solutions Class 7 Maths Chapter 1 — Large Numbers Around Us

Solution:

Step 1: In the Indian System, commas are placed after the hundreds, then after every two digits.

Step 2: The number 7,05,00,210 has groups: 210 (hundreds), 00 (thousands), 05 (lakhs), 7 (crores).

Step 3: Therefore, it is read as Seven crore, five lakh, two hundred ten.

Solution:

Step 1: Break down the number into its International System groups: 'Four hundred fifty-three million', 'two hundred one thousand', 'five hundred'.

Step 2: Four hundred fifty-three million is 453,000,000.

Step 3: Two hundred one thousand is 201,000.

Step 4: Five hundred is 500. Combining these gives 453,201,500.

Solution:

Step 1: The number 'Nine crore forty-five thousand six hundred two' means there are 9 crores, 0 lakhs, 45 thousands, 6 hundreds, 0 tens, and 2 ones.

Step 2: In the Indian System, this should be written as 9,00,45,602.

Step 3: Ravi wrote 9,45,602, which is nine lakh forty-five thousand six hundred two. He missed the 'lakhs' period completely, treating the number as if it only had lakh and thousand places, not crore.

Solution:

Step 1: In the Indian System, 1 Lakh = 1,00,000.

Step 2: In the International System, 1 Million = 1,000,000.

Step 3: To compare, divide 1 Million by 1 Lakh: 1,000,000 / 1,00,000 = 10.

Step 4: This means 1 Million is 10 times 1 Lakh, or 1 Lakh is 10 times smaller than 1 Million.

Solution:

Step 1: The number is 8,46,29,051.

Step 2: Starting from the right, the place values are: 1 (ones), 5 (tens), 0 (hundreds), 9 (thousands), 2 (ten thousands), 6 (lakhs), 4 (ten lakhs), 8 (crores).

Step 3: The digit 6 is in the 'lakhs' place.

Step 4: Therefore, its place value is 6 × 1,00,000 = 6,00,000.