1,00,000 - 75,000 = 25,000 less.

1,06,000 - 1,00,000 = 6,000 more.

1,06,000 - 75,000 = 31,000 increase.

180 - 40 = 140m taller.

450 - 40 = 410m taller.

450 / 4 = 112.5 ≈ 113 floors.

(a) Three lakh six hundred

(b) Five lakh four thousand eighty five

(c) Twenty seven lakh thirty thousand

(d) Seventy lakh fifty three thousand one hundred thirty eight

(a) 1,23,456

(b) 4,07,704

(c) 50,05,050

(d) 10,00,235

(b) 10 times

(c) 53 times

(d) 90 times

(e) 100 times

(g) 100

(a) 50 times

(b) 78 times

(c) 100 times

(d) 370 times

(e) 1000 times

(f) 10,000 times

(a) 4 times

(b) 37 times

(c) 100 times

(d) 530 times

(e) 900 times

(f) 976 times

(g) 1000 times

(i) 100

(j) 1000

(k) Yes, numbers not multiples of 100.

(5×1000) + (0×100) + (7×10) + (2×1) = 5072

(a) (8×1000) + (3×100) + (0×10) + (0×1)

(b) (4×10000) + (0×1000) + (6×100) + (2×10) + (9×1)

(c) (5×10000) + (6×1000) + (3×100) + (5×10) + (4×1)

(d) (6×10000) + (6×1000) + (6×100) + (6×10) + (6×1)

(e) (3×100000) + (6×10000) + (7×1000) + (8×100) + (1×10) + (3×1)

(a) 2×10000 + 0×1000 + 8×100 + 0×10 + 0×1

(b) 9×10000 + 2×1000 + 1×100 + 0×10 + 0×1

(c) 1×100000 + 2×10000 + 0×1000 + 5×100 + 0×10 + 0×1

(d) 6×1000000 + 5×100000 + 3×10000 + 0×1000 + 0×100 + 0×10 + 0×1

(e) 7×1000000 + 0×100000 + 2×10000 + 5×1000 + 7×100 + 0×10 + 0×1

1000 × 1,00,000 = 10,00,00,000 (8 zeros).

(a) Indian: Forty lakh fifty thousand six hundred seventy eight; American: Four million fifty thousand six hundred seventy eight.

(b) Indian: Four crore eighty one lakh twenty one thousand six hundred twenty; American: Forty eight million one hundred twenty one thousand six hundred twenty.

(c) Indian: Two crore two lakh twenty thousand two; American: Twenty million two hundred twenty thousand two.

(d) Indian: Twenty four crore sixty eight lakh thirteen thousand five hundred seventy nine; American: Two hundred forty six million eight hundred thirteen thousand five hundred seventy nine.

(e) Indian: Thirty four crore fifty lakh five hundred forty three; American: Three hundred forty five million five hundred forty three.

(f) Indian: One hundred two crore three lakh four thousand fifty; American: One billion twenty million three hundred four thousand fifty.

(a) 1,01,01,010

(b) 1,001,001,001

(c) 10,20,30,040

(d) 9,080,700,600

(a) 30,000 < 3,00,000

(b) 5,00,000 < 5,000,000

(c) 8,00,000 < 8,000,000

(d) 640,00,00,000 > 60,000,000,000

(a) Round up: Ordering food for party (guests 98 → order for 100).

(b) Round down: Budgeting expense (cost 472 → estimate 470).

(c) Either: Approximate distance (120km → 100 or 150).

(d) Exact: Exam marks, bank balance.

Thousand: 3,87,70,000

Ten thousand: 3,87,70,000

Lakh: 3,88,00,000

Ten lakh: 3,90,00,000

Crore: 4,00,00,000

Thousand: 29,05,32,000

Ten thousand: 29,05,30,000

Lakh: 29,05,00,000

Ten lakh: 29,00,00,000

Crore: 29,00,00,000

(a) Both correct, Estu closer.

(b) > 8,50,000 (both >4,00,000).

(c) < 8,83,128 (second <4,20,000).

(d) 8,82,810

(a) Both correct, Roxie closer.

(b) > 9,50,000 (14 lakh - 5 lakh = 9 lakh).

(c) > 9,63,128 (first >14 lakh).

(d) 9,73,108

Populations grew from 2001 to 2011, Mumbai largest.

“Population Growth in Major Indian Cities (2001-2011)”

31,15,431; increase 5,76,958 ≈ 6 lakh.

Bengaluru (41,24,644).

Bengaluru, Hyderabad, Ahmedabad, Surat, Pune, Jaipur.

1,24,42,373 / 16,84,222 ≈ 7.4 (8 times).

(a) 2×1768×50 = 1,76,800

(b) 72×125 = 9,000

(c) 125×40×8×25 = 10,00,000

(a) 300

(b) 6,000

(c) 30,000

(d) 30,000

(e) 4,80,000 × 25 = 1,20,00,000

11×11 = 121

111×111 = 12321

1111×1111 = 1234321

66×61 = 4026

666×661 = 440226

6666×6661 = 44402226

3×5 = 15

33×35 = 1155

333×335 = 111555

101×101 = 10201

102×102 = 10404

103×103 = 10609

5-digit × 5-digit = 9 or 10 digits

8-digit × 3-digit = 10 or 11 digits

12-digit × 13-digit = 24 or 25 digits

(a) 1 lakh × 5g = 5 lakh g = 500kg (yes, liftable? No, too heavy).

(b) 250/min × 1440 = 3,60,000 > 1 million? No, 3.6 lakh/day.

(c) 1/sec × 86,400 = 86,400 < 10 lakh (no).

(a) 2+8 = 10

(b) 9+2+1 = 12

(c) 12+0+5 = 17

(d) 6+5+3 = 14

(e) 7+0+2+5+7 = 21

(a) 70,000 + 30,000 + 10,000 = 1,10,000

(b) 1,50,000 + 70,000 - 20,000 = 2,00,000

(c) 1,50,000 + 4,00,000 - 20,000 = 5,30,000

(d) 1,50,000 × 8 + 5,000 = 12,05,000

(e) 1,50,000 × 14 - 5,000 = 20,95,000

5108: 5+2+2+4 = 13 sticks.

1. 42,019 = 23 sticks.

2. 42,078, 42,079, etc.

3. 42,019 → 421,019 (biggest).

4. 142,019, 412,019, etc.

1,00,000

36,500

25,000

180m

Three lakh six hundred

4 times

7

400

6,72,85,000

1,24,42,373

300

121

4,75,000

9,300

1,50,000

365 × 100 × 3 = 1,09,500 > 1 lakh (yes).

31,000

450 / 4 = 112.5 ≈ 113

One lakh twenty three thousand four hundred fifty six

10,000 times

Indian: One lakh; American: One hundred thousand

732 guests → 750 sweets

Approx 8,80,000

5,76,958 ≈ 6 lakh

9,000 (72 × 1000 / 8)

5 or 6 digits

4,00,00,000

3,844 days ≈ 10.5 years

500kg (heavy)

13

Chart: Crores, Lakhs, Thousands, Hundreds, Tens, Units. Example: 1,23,45,678 = 1 crore 23 lakh 45 thousand 678. Commas: 3-2-2 from right.

Indian: Lakh (1,00,000), Crore (1,00,00,000). American: Million (1,000,000), Billion (1,000,000,000). Example table.

Up: Party food. Down: Cost estimate. Either: Distance. Exact: Marks.

×100 / 4. Example: 72 × 25 = 1,800.

Min n+m-1 (10^{n-1} × 10^{m-1} = 10^{n+m-2}). Max n+m (99... × 99... ≈ 10^n × 10^m).

Bengaluru doubled, Mumbai grew 4 lakh, etc.

Teaches place value through adding multiples.

Kirtanas, Earth-Sun.

1 lakh buses × 50 = 50 lakh < Mumbai 1.24 crore (no).

888888 (24 sticks, number 888,888).