Question 11 Mark
$100$ thousands $=$ ________ lakh.
AnswerWe know that, $1$ lakh $= 100000$
$= 100 \times 1000$
$= 100$ thousands
View full question & answer→Question 21 Mark
By adding $1$ to the greatest __________ digit number, we get ten lakh.
AnswerWe know that, predecessor is one less than the given number.
$1000000 - 1 = 999999$
So, $999999$ is the greatest 6-digit number.
View full question & answer→Question 31 Mark
The $LCM$ of two numbers is greater than the larger of the numbers.
AnswerSince, $LCM$ of two numbers may be equal to or greater than the larger of the numbers.
View full question & answer→Question 41 Mark
Natural numbers are closed under addition.
AnswerSince, the sum of any two natural numbers is always a natural number.
View full question & answer→Question 51 Mark
$5555 = 5 \times 1000 + 5 \times 100 + 5 \times 10 + 5 \times 1$
AnswerSince, $5 \times 1000 + 5 \times 100 + 5 \times 10 + 5 \times 1 = 5000 + 500 + 50 + 5 = 5555$
View full question & answer→Question 61 Mark
Among kilo, milli and centi, the smallest is centi.
AnswerSince, among kilo, milli and centi, the smallest is milli.
View full question & answer→Question 71 Mark
$LCM$ of two or more numbers is divisible by their $HCF.$
View full question & answer→Question 81 Mark
$786 \times 3 + 786 \times 7 =$ ________
Answer$786 \times 3 + 786 \times 7 = 786 \times (3 + 7) = 786 \times 10 = 7860$
View full question & answer→Question 91 Mark
$400$ is the predecessor of ________.
AnswerWe know that, predecessor of any number is $1$ less than the number.
So, predecessor of $400 = 400 - 1 = 399$
View full question & answer→Question 101 Mark
A number, for which the sum of all its factors is equal to twice the number, is called a __________ number.
AnswerBy definition, a number, for which the sum of all its factors is equal to twice the number, is called perfect number.
View full question & answer→Question 111 Mark
There is a natural number which when added to a natural number, gives the natural number itself.
AnswerThere is no such natural number which when added to a natural number, gives the natural number itself.
View full question & answer→Question 121 Mark
The number $81652318$ will be read as eighty one crore six lakh fifty two thousand three hundred eighteen.
AnswerSince, the number $81652318$ will be read as eight crore sixteen lakh fifty two thousand three hundred eighteen.
View full question & answer→Question 131 Mark
Sum of two consecutive odd numbers is always divisible by $4.$
View full question & answer→Question 141 Mark
________ is the successor of the largest $3-$digit number.
AnswerWe know that,
largest $3-$digit number $= 999$
Successor of $999 = 999 + 1 $
$= 1000$
View full question & answer→Question 151 Mark
Height of a person is $1\ m\ 65\ cm.$ His height in millimetres is _________.
AnswerWe know that, $1\ m = 100\ cm$ and $1\ cm = 10\ mm$
$1\ m = 1000\ mm$ and $65\ cm = 65 × 10\ mm = 650\ mm$
So,
$1\ m\ 65\ cm = 1000\ mm + 650\ mm$
$= 1650\ mm$
View full question & answer→Question 161 Mark
$9128 \times $ ________ $= 9128$
Answer$9128 \times 1 = 9128$
Solution: If any number is multiplied by $1,$ then it gives the same number.
View full question & answer→Question 171 Mark
In Roman numeration, if a symbol is repeated, its value is multiplied as many times as it occurs.
AnswerSince, in Roman numeration, if a symbol is repeated, its value is added as many times as it occurs.
View full question & answer→Question 181 Mark
$2916\ \times $ _______ $= 0$
Answer$2916 \times 0 = 0$
Solution:
If any number is multiplied by zero, then their product is always zero.
View full question & answer→Question 191 Mark
A number is a ________ of each of its factors.
AnswerA number is a multiple of each of its factors. Solution: By general rule, a number is a multiple of each of its factors.
View full question & answer→Question 201 Mark
$HCF$ of two or more numbers may be one of the numbers.
AnswerIf all the numbers are multiples of same number, then the smallest number among them is their $HCF.$
View full question & answer→Question 211 Mark
On the following numbers, which is the greatest and which is the smallest? $38051425, 30040700, 67205602$
AnswerWe have, $38051425, 30040700$ and $67205602$
On comparing the given numbers. we get,
The greatest number $= 67205602$
the smallest number $= 30040700$
View full question & answer→Question 221 Mark
Predecessor of a two-digit number is always a two-digit number.
AnswerSince, predecessor of a two-digit number cannot be always a two digit number, e.g. Let a two-digit number be $10.$ Then, predecessor of $10 = 10 - 1 = 9$
View full question & answer→Question 231 Mark
Whole numbers are closed under ___________ and under ___________.
AnswerWhole numbers are closed under addition and under multiplication.
Solution:
If $a$ and $b$ are any two whole numbers, then $a + b = c ($whole numbers$).$
Also, $a \times b = c ($whole numbers$)$
View full question & answer→Question 241 Mark
If the sum of two distinct whole numbers is odd, then their difference also must be odd.
Question 251 Mark
$532235 = 5 \times 100000 + 3 \times 10000 + 2 \times 1000 + 2 \times 100 + 3 \times 10 + 5$
AnswerSince, $5 \times 100000 + 3 \times 10000 + 2 \times 1000 + 2 \times 100 + 3 \times 10 + 5 \times 1$
$= 500000 + 30000 + 2000 + 200 + 30 + 5 = 532235$
View full question & answer→Question 261 Mark
The number five crore twenty three lakh seventy eight thousand four hundred one can be written, using commas, in the Indian System of Numeration as ____________.
AnswerThe number five crore twenty three lakh seventy eight thousand four hundred one can be written, using commas, in the Indian System of Numeration as $5,23,78,401.$
View full question & answer→Question 271 Mark
If a number has _________ in ones place, then it is divisible by $10.$
AnswerIf a number has zero in ones place, then it is divisible by $10. $
View full question & answer→Question 281 Mark
Any non-zero whole number divided by itself, gives the quotient $1.$
AnswerIf a is any whole number, then $a + a = 1$
View full question & answer→Question 291 Mark
Addition is commutative for natural numbers.
AnswerIf $a$ and $b$ are two natural numbers, then
$a + b = b + a$
View full question & answer→Question 301 Mark
If the sum of the digits in a number is a of $3,$ then the number is _________ divisible by $3.$
AnswerIf the sum of the digits in a number is a of $3,$ then the number is multiple divisible by $3.$
View full question & answer→Question 311 Mark
If a whole number is divided by another whole number, which is greater than the first one, the quotient is not equal to zero.
Question 321 Mark
The largest $4-$digit number formed by the digits $6, 7, 0, 9$ using each digit only once, is $9760.$
AnswerSince, for making the largest number, we arrange the given digits in descending order. Descending order of the given digits is $9, 7, 6$ and $0.$
View full question & answer→Question 331 Mark
Of the given two natural numbers, the one having more digits, is greater.
Question 341 Mark
Length of river ‘Narmada’ is about $1290\ km.$ Its length in metres is __________.
AnswerLength of river ‘Narmada’ is about $1290\ km.$
Its length in metres is $1290000\ m.$
Solution:
We know that, $1\ km = 1000\ m$
$\therefore 1290\ km = 1290 \times 1000 = 1290000\ m$
View full question & answer→Question 351 Mark
In Roman numeration, a symbol is not repeated more than three times.
AnswerSince, it is a general rule.
View full question & answer→Question 361 Mark
There is a whole number which when added to a whole number, gives the number itself.
AnswerSince, if zero is added to any whole number, then the sum is the number itself.
View full question & answer→Question 371 Mark
$8925 \times 1 =$ _______
Answer$8925 \times 1 = 8925 $
View full question & answer→Question 381 Mark
The product of two whole numbers need not be a whole number.
AnswerWhole numbers are closed under multiplication.
View full question & answer→Question 391 Mark
If a number exactly divides the sum of three numbers, it must exactly divide the numbers separately.
AnswerIf a number divides three numbers exactly, it must divide their sum exactly, but vice-versa is not true.
View full question & answer→Question 401 Mark
If a number divides three numbe exactly, it must divide their sum exactly.
Question 411 Mark
If $0$ is subtracted from a whole number, then the result is the ________ itself.
AnswerIf $0$ is subtracted from a whole number, then the result is the number itself.
Solution:
If $a$ is any whole number, then $a - 0 = a$
View full question & answer→Question 421 Mark
The smallest $6-$digit natural number ending with $5$ is __________.
AnswerThe smallest $6-$digit natural number ending with $5$ is $100005.$
Solution:
We know that, smallest $6-$digit natural number $= 100000$
Smallest $6-$digit natural number ending with $5 = 100005$
View full question & answer→Question 431 Mark
The population of Pune was $2538473$ in $2001.$ Rounded off to nearest thousands, the population was __________.
AnswerThe population of Pune was $2538473$ in $2001.$ Rounded off to nearest thousands, the population was $2538000.$
Solution:
Rounded off $2538473$ to nearest thousands $= 2538000$
View full question & answer→Question 441 Mark
A number with three or more digits is divisible by $6,$ if the number formed by its last two digits (i.e. ones and tens) is divisible by $6.$
AnswerAccording to the divisibility test for $6,$ if a number is divisible by $2$ and $3$ both, then it is divisible by $6.$
View full question & answer→Question 451 Mark
A number with $4$ or more digits is divisible by $8,$ if the number formed by the last three digits is divisible by $8.$
AnswerAccording to the divisibility test for $8, 4$ or more digit number is divisible by $8,$ if the number formed by the last three digits is divisible by $8.$
View full question & answer→Question 461 Mark
$19 \times 12 + 19 = 19 \times (12 +$ _______$)$
Answer$19 \times 12 + 19 = 19 \times (12 + 1)$
Solution:
If $a, b$ and $c$ are three whole numbers, then,
$a \times b + a \times c = a(b + c) [$by distributive property$]$
View full question & answer→Question 471 Mark
The $LCM$ of two or more given numbers is the lowest of their common ___________.
AnswerThe $LCM$ of two or more given numbers is the lowest of their common multiples.
View full question & answer→Question 481 Mark
$a.\ 1$ metre $= .......$ millimetres.
$b.\ 1$ centimetre $= ........ $ millimetres.
$c.\ 1$ kilometre $= ....... $ millimetres.
Answer$a.$ We know that,
$10\ mm = 1\ cm$ and $100\ cm = 1\ m$
$1\ m = 1000\ mm$
$b.\ 1\ cm = 10\ mm$
$c.\ $ We know that,
$10\ mm = 1\ cm$
$100\ cm = m$ and $1000\ m = 1\ km$
$1\ km = 1000 \times 100 \times 10$
$= 1000000\ mm$ View full question & answer→Question 491 Mark
$39746 = 3 \times 10000 + 9 \times 1000 + 7 \times 100 + 4 \times 10 + 6$
AnswerSince, $3 \times 10000 + 9 \times 1000 + 7 \times 100 + 4 \times 10 + 6 \times 1$
$= 30000 + 9000 + 700 + 40 + 6 = 39746$
View full question & answer→Question 501 Mark
Estimated sum of $7826$ and $12469$ rounded off to hundreds is $20000.$
AnswerSince, rounded off $7826$ to nearest hundreds $= 7800$ And rounded off $12469$ to nearest hundreds $= 12500$
So, estimated sum $= 7800 + 12500 = 20300$
Here, $20300$ is nearest to $20000.$
So, the given statement is true.
View full question & answer→