Olympiad Test: Number Sense - Class 5 MCQ

The greatest six-digit number is 999999.
Therefore, predecessor of the greatest
six-digit number is
999999 – 1 = 999998.
Hence, the correct answer is C.

The given number is 45, 98, 351.
∴ Place value of 5 at Lakhs place in the given number = 5 × 100000 = 500000
Place value of 5 at Tens place in the given number = 5 × 10 = 50
∴ Difference between the place values of two 5’s in the given number = 500000 – 50 = 499950

Hence, the correct answer is A.

The given numbers are 9, 87, 61, 230 and 9, 87, 16, 230. Both of these numbers have 8 digits.

These two numbers can be written in
the place value table as follows:

Comparing the digits at ten thousands place, 6 > 1.

9, 87, 61, 230 > 9, 87, 16, 230.

Therefore, the sign “>” can be placed in the box.

Hence, the correct answer is A.

Successor of a number is the number that comes next to the given number and it can be obtained by adding 1 to the given number.

So, 10000001 is the successor of
10000000.

Hence, the correct answer is B.

The three-digit numbers that can be formed with the digits 3, 0 and 7 can be listed as 307, 370, 703, 730.
Thus, 4 three-digit numbers can be formed with the given digits without repetition.

Hence, the correct answer is C.

The given numbers can be placed in the place value table as follows:

It can be observed that the digits at lakhs place are the same.
On comparing the digits at ten thousands place, we get 2 > 1.
∴319240 is smallest amongst the given
numbers. Consider the numbers 321987, 321978 and 321970.
Here, the digits at thousands place are the same.
Also, the digits at hundreds place are the same. On comparing the digits at tens place, we get 8 > 7.
∴ 321987 > (321978, 321970)

Therefore, among the given numbers, 321987 and 319240 are the greatest and smallest numbers respectively

Hence, the correct answer is B.

The given digits are 3, 0, 9, 1 and 5. The greatest 5-digit number formed by using all the given digits is 95310.
The smallest 5-digit number formed by using all the given digits is 10359.

∴ Required difference
= 95310 – 10359 = 84951

It is known that 1 million =10 lakh and 1 crore = 100 lakh

∴ 1 crore = 10 × 10 lakh = 10 million

So, 3 crore = 3 × 10 million = 30 million

Therefore, 30 millions is equal to 3 crore.

Hence, the correct answer is B.

Fifty million twenty-one thousand two hundred and thirty-six can be written in International system of numeration as
50,021,236.

This number can be rewritten in Indian system of numeration as 5,00,21,236.

Hence, the correct answer is B.

1 billion = 1000 million and 1 million = 1000 thousands

It is known that 1000 > 10, 10000 > 216

∴ 1000 million > 10 million, 10000 million > 216 million

So, 1 billion > 10 million, 10 million
> 216 thousand

∴ 1 billion > 10 million > 216
thousand

Thus, the given numbers can be arranged in descending order as 1 billion, 10 million, 216 thousands

Hence, the correct answer is C.

The numbers 2,357,822 and 2,357,799
can be placed in place value table as

It is seen that the digits at million, hundred thousands, ten thousands and thousands place are the same.

Comparing the digits at hundreds place,
8 > 7.

Thus, 2,357,822 > 2,357,799

Hence, the correct answer is B.

It is known that 1 million = 1,000,000 35 million = 35,000,000

Therefore, there are six zeroes in 35
million.

Hence, the correct answer is C.

18 is composite because 18 can be written as a product of factors, not including 1 and 18 :

18 = 2×9 or 18 = 3×6.

19 is prime because 19 doesn’t have
any factors except 1 and 19.

20 is composite because 20 can be written as a product of factors, not including 1 and 20 :

20 = 2×10 or 20 = 4×5

21 is composite because 21 can be written as a product of factors, not including 1 and 21 : 21 = 3×7

26 is composite because 26 can be written as a product of factors, not including 1 and 26 :

26 = 2 × 13.

27 is composite because 27 can be written as a product of factors, not including 1 and 27:

27 = 3 × 3 × 3 or 3³

28 is composite because 28 can be written as a product of factors, not including 1 and 28:

28 = 4 × 7 or 2² × 7.

29 is prime because 29 doesn’t have any factors except 1 and 29.

• A composite number has more than two distinct positive divisors.
• 69 can be divided by 1, 3, 23, and 69, making it composite.
• In contrast, 67, 71, and 73 have only two divisors: 1 and themselves, so they are prime numbers.
• Thus, among the options, 69 is the only composite number.

105 = 3 × 35 or 3 × 5 × 7, and so is composite.

101, 103 and 107 are all prime numbers.

2 and 3 are prime numbers; 4, 6 and 8 are composite numbers.

All the products are correct, but only answer D is a product of prime factors

Prime numbers are the numbers that have only 2 factors i.e. 1 and itself. Composite numbers are the numbers that have at least 3 or more than 3 factors.
2, 3 and 5 are prime numbers; 6, 9 and
15 are composite numbers.

All the products are correct, but only
answer B has a product of prime factors.

To determine the place value of 5 in the number 780756, we look at its position from right to left.

The number 780756 can be broken down as follows:

• 6 is in the ones place.
• 5 is in the tens place.
• 7 is in the hundreds place.
• 0 is in the thousands place.
• 8 is in the ten thousands place.
• 7 is in the hundred thousands place.

Therefore, the 5 in 780756 is in the tens place.

So, the correct answer is: Five tens

Place value of 5 in
750 = 5 × 10 = 50
17510 = 5 × 100 = 500
124605 = 5 × 1 = 5
50630 = 5 × 10000 = 50000