Solutions to Class Six English Version Mathematics Chapter 1 Exercise 1.1 Solutions (2025 curriculum)
1. Write down the following numbers in digits
(a) Twenty thousand seventy ; thirty thousand eight ; fifty five thousand four hundred
Answer:
Steps:
Break each number phrase into thousands, hundreds, tens, and units. Write the digits accordingly.
Solution:
Twenty thousand seventy = 20000 + 70 = 20070
Thirty thousand eight = 30000 + 8 = 30008
Fifty five thousand four hundred = 55000 + 400 = 55400
Ans: 20070 ; 30008 ; 55400
Explanation:
When writing numbers in digits, identify the value of each worded part (thousand, hundred, tens, units) and add them. There's no need to add zeros unnecessarily—just place digits in correct positions.
(b) Four lac five thousand ; seven lac two thousand seventy five
Answer:
Steps:
Convert 'lac' to 100,000 and add the remaining parts (thousands, hundreds, tens, units).
Solution:
Four lac = 400000, five thousand = 5000 → 400000 + 5000 = 405000
Seven lac = 700000, two thousand = 2000, seventy five = 75 → 700000 + 2000 + 75 = 702075
Ans: 405000 ; 702075
Explanation:
Use Indian place value system. 1 lac = 100000. So calculate by separating and then adding components.
(c) Seventy six lac nine thousand seventy ; Thirty lac nine hundred four
Answer:
Steps:
Split number into lacs, thousands, hundreds, tens, and units.
Solution:
Seventy six lac = 7600000, nine thousand = 9000, seventy = 70 → Total = 7609070
Thirty lac = 3000000, nine hundred four = 904 → Total = 3000904
Ans: 7609070 ; 3000904
Explanation:
Identify place values and combine them accurately. Remember Indian place value names like lac, crore.
(d) Five crore three lac two thousand seven
Answer:
Steps:
Use crore = 10000000, lac = 100000, thousand = 1000. Add all parts.
Solution:
Five crore = 50000000
Three lac = 300000
Two thousand = 2000
Seven = 7
→ Total = 50302007
Ans: 50302007
Explanation:
Add values of crore, lac, thousand and unit separately. No need for zero padding between parts.
(e) Ninety eight crore seven lac five thousand nine
Answer:
Steps:
Convert crore to 10 million, lac to hundred thousand, and sum the parts.
Solution:
Ninety eight crore = 980000000
Seven lac = 700000
Five thousand = 5000
Nine = 9
→ Total = 987005009
Ans: 987005009
Explanation:
Each segment is based on Indian number system. Break them into individual values and combine.
(f) One hundred two crore five thousand seven hundred eight
Answer:
Steps:
Convert crore to 10 million, then add thousands, hundreds, and units.
Solution:
102 crore = 1020000000
Five thousand = 5000
Seven hundred = 700
Eight = 8
→ Total = 1020005708
Ans: 1020005708
Explanation:
Straight addition after breaking the words into number components.
(g) Nine hundred fifty five crore seven lac ninety
Answer:
Steps:
Convert crore, lac and tens.
Solution:
955 crore = 9550000000
Seven lac = 700000
Ninety = 90
→ Total = 9550700090
Ans: 9550700090
Explanation:
Be careful with place values when some digits are missing (like hundreds or units).
(h) Three thousand five hundred crore eighty five lac nine hundred twenty one
Answer:
Steps:
Break it down as follows:
3500 crore = 35000000000
85 lac = 8500000
Nine hundred twenty one = 921
→ Add all
Solution:
35000000000 + 8500000 + 921 = 35008500921
Ans: 35008500921
Explanation:
In large numbers, break into parts and add step-by-step to avoid mistakes.
(i) Fifty billion three hundred one million five hundred thirty eight thousand
Answer:
Steps:
Convert:
1 billion = 1000000000
1 million = 1000000
1 thousand = 1000
Then add parts:
Fifty billion = 50000000000
Three hundred one million = 301000000
Five hundred thirty eight thousand = 538000
Solution:
50000000000 + 301000000 + 538000 = 50301538000
Ans: 50301538000
Explanation:
Use International Number System. Ensure unit conversion is correct:
Billion → 1,000,000,000
Million → 1,000,000
Thousand → 1,000
2. Read the following numbers and write them in words
(a) 45789 ; 41007 ; 891071
Answer:
Steps:
Group digits according to Indian Number System: ones, tens, hundreds, thousands, lacs.
Solution:
45789 = Forty five thousand seven hundred eighty nine
41007 = Forty one thousand seven
891071 = Eight lac ninety one thousand seventy one
Ans:
Forty five thousand seven hundred eighty nine
Forty one thousand seven
Eight lac ninety one thousand seventy one
Explanation:
Indian system groups digits like: ##,##,### (e.g., 8,91,071 = Eight lac ninety one thousand seventy one)
(b) 200078 ; 790678 ; 890075
Answer:
Steps:
Break into parts using lacs and thousands.
Solution:
200078 = Two lac seventy eight
790678 = Seven lac ninety thousand six hundred seventy eight
890075 = Eight lac ninety thousand seventy five
Ans:
Two lac seventy eight
Seven lac ninety thousand six hundred seventy eight
Eight lac ninety thousand seventy five
Explanation:
200078 → 2,00,078 = 2 lac + 78; rest follow typical grouping.
(c) 4400785 ; 6870509 ; 7105070
Answer:
Steps:
These are in tens of lacs. Break using crore, lac, thousand, hundred structure.
Solution:
4400785 = Forty four lac seven hundred eighty five
6870509 = Sixty eight lac seventy thousand five hundred nine
7105070 = Seventy one lac five thousand seventy
Ans:
Forty four lac seven hundred eighty five
Sixty eight lac seventy thousand five hundred nine
Seventy one lac five thousand seventy
Explanation:
E.g., 44,00,785 → Forty four lacs + seven hundred eighty five
(d) 50877003 ; 94309799 ; 83900765
Answer:
Steps:
These are in crore range. Group like: crore, lac, thousand, etc.
Solution:
50877003 = Five crore eight lac seventy seven thousand three
94309799 = Nine crore forty three lac nine thousand seven hundred ninety nine
83900765 = Eight crore thirty nine lac seven hundred sixty five
Ans:
Five crore eight lac seventy seven thousand three
Nine crore forty three lac nine thousand seven hundred ninety nine
Eight crore thirty nine lac seven hundred sixty five
Explanation:
Break numbers into groups: crore-lac-thousand-hundred-units to spell them correctly.
3. Determine the place value of the significant digits in the following numbers:
(a) 72
Answer:
Steps:
We look at each digit and identify its place value (tens, units).
7 is in the tens place
2 is in the units place
Solution:
Place value of 7 = 7 × 10 = 70
Place value of 2 = 2 × 1 = 2
Ans: 70, 2
Explanation:
Each digit has a place value based on its position from right to left: units (×1), tens (×10), hundreds (×100), etc.
(b) 359
Answer:
Steps:
3 is in the hundreds place
5 is in the tens place
9 is in the units place
Solution:
Place value of 3 = 3 × 100 = 300
Place value of 5 = 5 × 10 = 50
Place value of 9 = 9 × 1 = 9
Ans: 300, 50, 9
Explanation:
Leftmost digit = highest place value (hundreds here). Multiply digit by its position value.
(c) 4203
Answer:
Steps:
4 is in thousands, 2 in hundreds, 0 in tens, 3 in units
Solution:
4 × 1000 = 4000
2 × 100 = 200
0 × 10 = 0
3 × 1 = 3
Ans: 4000, 200, 0, 3
Explanation:
Each digit multiplied by its position value gives its place value.
(d) 70809
Answer:
Steps:
Positions: 7 (ten-thousands), 0 (thousands), 8 (hundreds), 0 (tens), 9 (units)
Solution:
7 × 10000 = 70000
0 × 1000 = 0
8 × 100 = 800
0 × 10 = 0
9 × 1 = 9
Ans:70000, 0, 800, 0, 9
Explanation:
Even 0s have place values, but their final value becomes 0 after multiplication.
(e) 130045078
Answer:
Steps:
From left:
1 (ten-crore), 3 (crore), 0 (ten-lac), 0 (lac), 4 (ten-thousand), 5 (thousand), 0 (hundred), 7 (ten), 8 (unit)
Solution:
1 × 100000000 = 100000000
3 × 10000000 = 30000000
0 × 1000000 = 0
0 × 100000 = 0
4 × 10000 = 40000
5 × 1000 = 5000
0 × 100 = 0
7 × 10 = 70
8 × 1 = 8
Ans:100000000, 30000000, 0, 0, 40000, 5000, 0, 70, 8
Explanation:
Use Indian Number System positions: Ten Crore → Crore → Ten Lac → Lac → Ten Thousand → Thousand → Hundred → Ten → Unit
(f) 250009709
Answer:
Steps:
Break the digits: 2 (ten-crore), 5 (crore), 0 (ten-lac), 0 (lac), 0 (ten-thousand), 9 (thousand), 7 (hundred), 0 (ten), 9 (unit)
Solution:
2 × 100000000 = 200000000
5 × 10000000 = 50000000
0 × 1000000 = 0
0 × 100000 = 0
0 × 10000 = 0
9 × 1000 = 9000
7 × 100 = 700
0 × 10 = 0
9 × 1 = 9
Ans: 200000000, 50000000, 0, 0, 0, 9000, 700, 0, 9
Explanation:
Even though there are many 0s, you still account for each place. Multiply each digit by its positional value.
(g) 5900007845
Answer:
Steps:
This is a 10-digit number. Start from the left:
5 (thousand-crore), 9 (hundred-crore), 0 (ten-crore)... and so on
Solution:
5 × 1000000000 = 5000000000
9 × 100000000 = 900000000
0 × 10000000 = 0
0 × 1000000 = 0
0 × 100000 = 0
0 × 10000 = 0
7 × 1000 = 7000
8 × 100 = 800
4 × 10 = 40
5 × 1 = 5
Ans: 5000000000, 900000000, 0, 0, 0, 0, 7000, 800, 40, 5
Explanation:
Ten-digit numbers extend up to Arabs (thousand-crore) in the Indian system. Start at left-most digit and assign position values downward.
(h) 900758432
Answer:
Steps:
Break digits according to place value chart.
Solution:
9 × 100000000 = 900000000
0 × 10000000 = 0
0 × 1000000 = 0
7 × 100000 = 700000
5 × 10000 = 50000
8 × 1000 = 8000
4 × 100 = 400
3 × 10 = 30
2 × 1 = 2
Ans: 900000000, 0, 0, 700000, 50000, 8000, 400, 30, 2
Explanation:
Start from crores and go down to units. Ignore zero multiplications in result, but still list the place values.
(i) 105789023004
Answer:
Steps:
This is a 12-digit number, so we start from kharab place if using Indian system (or billion in international).
Solution:
1 × 100000000000 = 100000000000
0 × 10000000000 = 0
5 × 1000000000 = 5000000000
7 × 100000000 = 700000000
8 × 10000000 = 80000000
9 × 1000000 = 9000000
0 × 100000 = 0
2 × 10000 = 20000
3 × 1000 = 3000
0 × 100 = 0
0 × 10 = 0
4 × 1 = 4
Ans:100000000000, 0, 5000000000, 700000000, 80000000, 9000000, 0, 20000, 3000, 0, 0, 4
Explanation:
Each digit is multiplied by its respective power of 10, based on its position from right to left.
4. Write down the greatest and the smallest numbers consisting of nine digits.
Answer:
Steps:
To solve this, we consider:
The greatest 9-digit number will be made by putting all 9s
The smallest 9-digit number will have a 1 followed by eight 0s
Solution:
Greatest 9-digit number = 999999999
Smallest 9-digit number = 100000000
Ans:
Greatest = 999999999
Smallest = 100000000
Explanation:
A 9-digit number means it should have exactly 9 digits:
The greatest one is when every digit is the highest possible → all 9s
The smallest one starts with 1 followed by zeros → it's the smallest number that has exactly 9 digits (just above 8-digit max = 99999999)
5. Write the numeral for each of the following:
(a) Eight crore seventy lakh twenty-three thousand one hundred two
Answer:
Steps:
Break the number into parts:
8 crore = 8,00,00,000
70 lakh = 70,00,000
23 thousand = 23,000
102 = 102
Add all parts together.
Solution:
= 8,00,00,000 + 70,00,000 + 23,000 + 102
= 8,70,23,102
Ans: 8,70,23,102
Explanation:
We write each term numerically and sum them together to get the final numeral using the Indian Number System.
(b) Seventy crore five lakh thirty-two
Answer:
Steps:
Break the number into parts:
70 crore = 70,00,00,000
5 lakh = 5,00,000
32 = 32
Add all parts.
Solution:
= 70,00,00,000 + 5,00,000 + 32
= 70,05,00,032
Ans: 70,05,00,032
Explanation:
Follow Indian number system by splitting and aligning the place values correctly.
(c) Twenty-three crore twenty-three lakh twenty-three thousand twenty-three
Answer:
Steps:
Break into:
23 crore = 23,00,00,000
23 lakh = 23,00,000
23 thousand = 23,000
23 = 23
Solution:
= 23,00,00,000 + 23,00,000 + 23,000 + 23
= 23,23,23,023
Ans: 23,23,23,023
Explanation:
It’s a repeating pattern, so identify each place value and write them one by one.
(d) Forty-three crore five thousand seven
Answer:
Steps:
Break the phrase:
43 crore = 43,00,00,000
5 thousand = 5,000
7 = 7
Add together.
Solution:
= 43,00,00,000 + 5,000 + 7
= 43,00,05,007
Ans: 43,00,05,007
Explanation:
Even if some places are missing (like lakh, hundred, tens), we can use 0s in those places to keep the number structure correct.
6. Write the number names of the following numerals:
(a) 38705201
Answer:
Steps:
Break it according to the Indian Number System:
3,87,05,201 → Crores, Lakhs, Thousands, Hundreds
Solution:
= Three crore eighty-seven lakh five thousand two hundred one
Ans: Three crore eighty-seven lakh five thousand two hundred one
Explanation:
In the Indian Number System:
First 2 digits from right = Hundred/Tens/Units
Next two = Thousands
Next two = Lakhs
Remaining = Crores
(b) 60000000
Answer:
Steps:
60,000,000 → 6,00,00,000
Solution:
= Six crore
Ans: Six crore
Explanation:
Only the crore place has value; all others are 0.
(c) 32050002
Answer:
Steps:
Break as: 3,20,50,002
Solution:
= Three crore twenty lakh fifty thousand two
Ans: Three crore twenty lakh fifty thousand two
Explanation:
Keep breaking by 2 digits from right after hundreds to group as per Indian format.
(d) 50500505
Answer:
Steps:
Break as: 5,05,00,505
Solution:
= Five crore five lakh five hundred five
Ans: Five crore five lakh five hundred five
Explanation:
Even if some groups like thousands are missing, just skip them and write what is present.
(e) 10900000
Answer:
Steps:
Break as: 1,09,00,000
Solution:
= One crore nine lakh
Ans: One crore nine lakh
Explanation:
Zeros at the end do not change the value; only the crore and lakh places have non-zero values.
7. Write the successor and the predecessor of the following numbers:
(a) 5699
Answer:
Steps:
Successor = Number + 1
Predecessor = Number – 1
Solution:
Successor = 5699 + 1 = 5700
Predecessor = 5699 − 1 = 5698
Ans:
Successor: 5700
Predecessor: 5698
Explanation:
The successor of a number is the next number after it.
The predecessor is the number just before it.
(b) 9999
Answer:
Steps:
Add and subtract 1
Solution:
Successor = 9999 + 1 = 10000
Predecessor = 9999 − 1 = 9998
Ans:
Successor: 10000
Predecessor: 9998
Explanation:
Moving from 9999 to 10000 is a change in digit places, still follows the +1 rule.
(c) 10000
Answer:
Steps:
Add and subtract 1
Solution:
Successor = 10000 + 1 = 10001
Predecessor = 10000 − 1 = 9999
Ans:
Successor: 10001
Predecessor: 9999
Explanation:
Even large round numbers follow the same simple logic: ±1.
(d) 999999
Answer:
Steps:
Add and subtract 1
Solution:
Successor = 999999 + 1 = 1000000
Predecessor = 999999 − 1 = 999998
Ans:
Successor: 1000000
Predecessor: 999998
Explanation:
Crossing a place value (like going from lakhs to millions) still just adds 1.
(e) 1000000
Answer:
Steps:
Add and subtract 1
Solution:
Successor = 1000000 + 1 = 1000001
Predecessor = 1000000 − 1 = 999999
Ans:
Successor: 1000001
Predecessor: 999999
Explanation:
Same logic – numbers before and after any given number are found using ±1.
