Math Trivia : Round off the 3rd digit number from the top of the 123rd power of 2
I round off the 3rd digit number from the top of the number of 123rd power of 2. Find two digits number from the top of this number.
Answer
11
Solution
2^10 = 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 = 1024
2^20 = 2^10×2^10
2^20 = 1024 × 1024 = 1048576
2^40 = 1048576 × 1048576
2^40 ~~ 1048000 × 1048000 = 1098304000000
= (2^40 × 2) × (2^40 × 2) × (2^40 x 2)
2^40 × 2 ~~ 1098304000000 × 2 = 219600-------.
219600----- ~~ 220000---.
2^40 × 2 ~~ 1098304000000 × 2 = 219600-------.
219600----- ~~ 220000---.
2^123 ~~ (220000---) × (220000---) × (220000---)
~~ 1064800------.
Round off the 3rd digit number of 1064800-------, then it is 1100000------.
Round off the 3rd digit number of 1064800-------, then it is 1100000------.
