Question 1(a)
Continue: 456, 567, 678, …
Add 111 each time.
789, 900, 1,011, 1,122
Answer
789, 900, 1,011, 1,122
CLASS 5 · MATHS MELA · CHAPTER 1
Read, compare, round and regroup five-digit numbers while solving travel calculations and logical puzzles.
75 worked answers · short steps first, explanations when you need them
Textbook pages 5–7
Question 1(a)
Add 111 each time.
789, 900, 1,011, 1,122
789, 900, 1,011, 1,122
Question 1(b)
Add 1,050 each time.
2,100, 5,250, 6,300, 7,350
2,100, 5,250, 6,300, 7,350
Question 1(c)
Add 900 each time.
8,201, 9,101, 10,001, 10,901
8,201, 9,101, 10,001, 10,901
Question 1(d)
Add 100 each time.
10,400, 10,500, 10,600, 10,700, 10,800, 10,900, 11,000
10,400, 10,500, 10,600, 10,700, 10,800, 10,900, 11,000
Question 1(e)
Add 20 each time.
10,145, 10,165, 10,185, 10,205, 10,225, 10,245, 10,265, 10,285
10,145, 10,165, 10,185, 10,205, 10,225, 10,245, 10,265, 10,285
Question 1(f)
Add 1 each time.
10,994, 10,995, 10,996, 10,997, 10,998, 10,999, 11,000, 11,001
10,994, 10,995, 10,996, 10,997, 10,998, 10,999, 11,000, 11,001
Question 1(g)
Add 2 each time.
10,800, 10,802, 10,804, 10,806, 10,808, 10,810, 10,812
10,800, 10,802, 10,804, 10,806, 10,808, 10,810, 10,812
Question 1(h)
Subtract 1,001 each time.
71,003, 70,002, 69,001, 68,000, 66,999, 65,998, 64,997, 63,996
71,003, 70,002, 69,001, 68,000, 66,999, 65,998, 64,997, 63,996
Question 1(i)
Add 1,000 each time.
84,350, 85,350, 86,350, 87,350, 88,350, 89,350, 90,350, 91,350
84,350, 85,350, 86,350, 87,350, 88,350, 89,350, 90,350, 91,350
Question 2
7,209: seven thousand two hundred nine; 10,599: ten thousand five hundred ninety-nine; ten thousand seven hundred forty-three: 10,743.
13,579: thirteen thousand five hundred seventy-nine; ten thousand ten: 10,010; fifty-six thousand four hundred ninety-one: 56,491.
45,045: forty-five thousand forty-five; 39,593: thirty-nine thousand five hundred ninety-three; 50,005: fifty thousand five.
26,050: twenty-six thousand fifty; 81,200: eighty-one thousand two hundred; ninety thousand nine: 90,009; twenty-three thousand two hundred thirty: 23,230; thirty-six thousand one: 36,001.
The completed entries are 7,209; 10,599; 10,743; 13,579; 10,010; 56,491; 45,045; 39,593; 50,005; 26,050; 81,200; 90,009; 23,230; and 36,001 with the names shown.
Question 3
Compare ten-thousands first, then thousands, hundreds, tens and ones.
18,926 < 34,407 < 34,740 < 40,347 < 40,473 < 47,340 < 73,404 < 74,430.
Question 4
9,990 has no ten-thousands digit; it is below 10,000.
49,014 is above 40,000.
No. 9,990 < 49,014. The first 9 is in the thousands place, while 4 is in the ten-thousands place.
Question 4 · number line
The interval is 5,000 at every tick.
5,000, 10,000, 15,000, 20,000, 25,000, 30,000, 35,000, 40,000, 45,000, 50,000.
Question 5(a)
Swap the 1 and 7.
The result is 7,418.
One valid answer is 7,418.
Question 5(b)(i)
Swap 0 and 3.
10,593 becomes 13,590.
13,590.
Question 5(b)(ii)
Swap 1 and 5.
The result is 50,193.
50,193.
Question 5(c)(i)
Move the smallest available digit 2 to the first place by swapping it with the first 4.
28,447.
Question 5(c)(ii)
Move 8 to the first place by swapping it with the first 4.
84,247.
Textbook pages 7–9
Question Rabbit · hundreds
Distances: to 2,300 is 46; to 2,400 is 54.
2,300 is nearest; it takes 46 jumps.
Question Rabbit · thousands
Distances: to 2,000 is 346; to 3,000 is 654.
2,000 is nearest; it takes 346 jumps.
Question Table
3,176 → 3,180; 3,200; 3,000.
4,017 → 4,020; 4,000; 4,000.
5,789 → 5,790; 5,800; 6,000.
8,203 → 8,200; 8,200; 8,000.
Rows: (3,180, 3,200, 3,000); (4,020, 4,000, 4,000); (5,790, 5,800, 6,000); (8,200, 8,200, 8,000).
Question Think 1
7,030 rounds to 7,000 in both ways.
6,999 also rounds to 7,000 in both ways.
7,030 and 6,999.
Question Think 2(a)
21 and 24 both round to 20.
Example: 21 and 24.
Question Think 2(b)
241 and 249 both round to 200.
Example: 241 and 249.
Question Think 2(c)
2,210 and 2,440 both round to 2,000.
Example: 2,210 and 2,440.
Question Think 3(a)
121 and 124 both round to 120 and to 100.
Example: 121 and 124.
Question Think 3(b)
2,210 and 2,240 both round to 2,200 and 2,000.
Example: 2,210 and 2,240.
Question Think 3(c)
2,211 and 2,214 both round to 2,210; 2,200; 2,000.
Example: 2,211 and 2,214.
Textbook pages 10–11
Question 1
15×4=60.
60 km.
Question 2(a)
Students=461+439=900.
900÷2=450.
450 bicycles.
Question 2(b)
Students=461+439=900.
900÷3=300.
300 autorickshaws.
Question 2(c)
Students=461+439=900.
900÷4=225.
225 cars.
Question 2(d)
Students=461+439=900.
900÷6=150.
150 big cars.
Question 2(e)
Students=461+439=900.
900÷10=90.
90 tempo travellers.
Question 2(f)
Students=461+439=900.
900÷20=45.
45 boats.
Question 2(g)
Students=461+439=900.
900÷25=36.
36 minibuses.
Question 2(h)
Students=461+439=900.
900÷180=5.
5 aeroplanes.
Question Large counts
Possible textbook example: about 10,000 words.
Possible classroom example: 4,000 floor tiles or small grid squares; possible tree: thousands of leaves.
Possible town example: population, houses or vehicles.
Answers depend on observation; state what is counted and how the estimate was made.
Textbook pages 11–13
Question 1
Take sheep across; return alone.
Take lion across; bring sheep back.
Take grass across; return alone.
Take sheep across again.
All three cross safely in 7 one-way trips.
Question 2
With equal piles, the player moving second can mirror every first-player move in the other pile.
After each pair of moves the piles are equal again; the mirror player takes the final pebbles.
Choose to play second and always remove from the other pile exactly what the first player removed.
Question 3(1)
For digits a>b, (10a+b)−(10b+a)=9(a−b).
Every difference is a multiple of 9.
Question 3(2)
Every positive result remains a multiple of 9.
The only positive one-digit multiple of 9 is 9.
The process eventually reaches 9 for any two distinct starting digits.
Question 3(3)
First difference is 9 times the digit difference.
It is one digit only when the digit difference is 1.
Choose consecutive digits, such as 3 and 4 or 8 and 9.
Question 3(4)
27=9×3, so the digits must differ by 3.
Examples: 1 and 4, 2 and 5, or 6 and 9.
Question 3(5) · table
Use pairs (0,2),(0,3),(0,5),(0,7).
20−02=18; 30−03=27; 50−05=45; 70−07=63.
Rows may be 0,2→18; 0,3→27; 0,5→45; 0,7→63.
Question 3(5) · third subtraction
Starting digit difference 3 gives 27→45→9.
Starting digit difference 8 gives 72→45→9.
Any pair of digits differing by 3 or 8.
Question 3(5) · maximum
Difference 2 gives 18→63→27→45→9.
Difference 9 gives 81→63→27→45→9.
Pairs differing by 2 or 9 take 5 subtractions, the maximum.
Textbook pages 13–16
Question 1
Choose any integers above the first and below the second.
Example: 23,569; 23,700; 23,999; 24,100; 24,233.
Question 2
Choose values from 38,126 through 38,599.
Example: 38,126; 38,200; 38,350; 38,500; 38,599.
Question 3
67 thousand is greater than 56 thousand.
Sheetal’s car has been driven more.
Question 4
Arrange from the smallest ten-thousands digit upward.
₹39,999 < ₹49,900 < ₹89,999 < ₹90,000 < ₹93,743 < ₹94,983.
Question 5
Compare 66,540;65,232;56,380;53,231;51,336;45,858.
Town 6, Town 1, Town 3, Town 2, Town 4, Town 5.
Question 6
These are whole thousands from 43,000 through 53,000.
43,000; 44,000; 45,000; 46,000; 47,000; 48,000; 49,000; 50,000; 51,000; 52,000; 53,000.
Question 7(b)
8,000 + 60 + 2
8,000 + 60 + 2.
Question 7(c)
9,000 + 900 + 80
9,000 + 900 + 80.
Question 7(d)
10,000 + 300 + 4
10,000 + 300 + 4.
Question 7(e)
20,000 + 3,000 + 4
20,000 + 3,000 + 4.
Question 7(f)
70,000 + 400 + 5
70,000 + 400 + 5.
Question 8(b)
68−18=50=5 tens.
5 tens.
Question 8(c)
607−400=207.
207 ones.
Question 8(d)
After 4,000 and 20, 1,601 remains.
1,601=16 hundreds+1 one.
16 hundreds and 1 one.
Question 8(e)
20 hundreds=2,000. Choose 5 thousands; remainder=69.
5 thousands and 69 ones.
Question 8(f)
Choose 2 ten-thousands: 20,000+17,000=37,000.
Remaining 608=6 hundreds+8 ones.
2 ten-thousands and 6 hundreds.
Question 8(g)
43,001−30,000−1=13,000.
13 thousands and 0 hundreds.
Question 9(a)
Use whole-number division; ignore any remainder.
The quotient is 793.
793.
Question 9(b)
Use whole-number division; ignore any remainder.
The quotient is 79.
79.
Question 9(c)
Use whole-number division; ignore any remainder.
The quotient is 7.
7.
Question 9(d)
Use whole-number division; ignore any remainder.
The quotient is 15.
15.
Question 9(e)
Use whole-number division; ignore any remainder.
The quotient is 6534.
6534.
Question 9(f)
Use whole-number division; ignore any remainder.
The quotient is 653.
653.
Question 9(g)
Use whole-number division; ignore any remainder.
The quotient is 65.
65.
Question 9(h)
Use whole-number division; ignore any remainder.
The quotient is 130.
130.
Question King’s horses · mistake
Four side-counts total 20 appearances.
The one horse in a corner belongs to two sides and was counted twice.
There are 19 distinct horses; the caretaker double-counted the corner horse.
Question King’s horses · 18
The four sides need 20 appearances.
Place horses in two corner cells so those two horses are each counted twice; fill the remaining side positions to total 5 per side.
Use exactly two occupied corners and 16 other side horses, balanced so every side counts 5.
Question King’s horses · limit
At most all four corners can be occupied.
Minimum distinct horses=20−4=16.
Two more horses can be stolen; 16 is the minimum possible.