Using all digits from 0-9 exactly once (the first digit cannot be 0) to create a 10-digit number. Class 7

Using all digits from 0-9 exactly once (the first digit cannot be 0) to create a 10-digit number. Class 7

Question 1.

Using all digits from 0-9 exactly once (the first digit cannot be 0) to create a 10-digit number, write the : Class 7

(a) Largest multiple of 5

(b) Smallest even number

Solution:

(a) 9876543210

(b) 1234567890

Question 2.

The number 10,30,285 in words is Ten lakh thirty thousand two hundred eighty five, which has 41 letters. Give a 7-digit number name which has the maximum number of letters. Class 7

Solution:

The number is 73,73,773. Its number name is seventy three lakh seventy three thousand seven hundred seventy three. It has 60 letters.

Question 3.

Write a 9-digit number where exchanging any two digits results in a bigger number. How many such numbers exist? Class 7

Solution:

Such a number is 123456789.

Only one such number.

Question 4.

Strike out 10 digits from the number 12345123451234512345 so that the remaining number is as large as possible. Class 7

Solution:

On striking out the 10 digits as shown above, the largest number is 5534512345.

Question 5.

The words ‘zero’ and ‘one’ share letters ‘e’ and ‘o’. The words ‘one’ and ‘two’ share a letter ‘o’, and the words ‘two’ and ‘three’ also share a letter ‘t’. How far do you have to count to find two consecutive numbers which do not share an English letter in common? Class 7

Solution:

We may go on counting for any time, but we shall never get such numbers.