Estimate to the nearest `10,000(4,500,982,344)/(5.042xx10^(4))`'

An athlete in the Olympic gamed covers a distance of 100 m in 10 s . His kinetic energy can be estimated to be in range. (1) 200 J - 500 J (2) 2 xx 10^(5) J - 3 xx 10^(5) J (3) 20,000 J - 50,000 J (4) 2,000 J - 5,000 J .

Give arough estimate (by rounding off the nearest hundreds)and also a closer estimate(by rounding off to nearest tens), 4,89,348-48,365 .

Estimate the product by estimating each term to : a. its greatest place b. nearest 10 (i) 458xx512 (ii) 297xx716 (iii) 782xx403 (iv) 726xx501

Values of K_b for methanamine, dimethylamine and trimethylamine are 4.5xx10^(-4), 5.4xx10^(-4) "and" 0.6xx10^(-4) respectively. Select the strongest base.

Calculate the following a. (6.7 xx 10^(5)) xx (4.6 xx 10^(4)) b. (7.6 xx 10^(7)) xx (3.8 xx 10^(-4)) c. (6.8 xx 10^(-3)) xx (5.2 xx 10^(-4)) d. (6.7 xx 10^(5)) / (4.6 xx 10^(4)) e. (7.6 xx 10^(7)) / (3.8 xx 10^(-4)) f. (6.8 xx 10^(-3)) / (3.8 xx 10^(-4)) g. 7.65 xx 10^(2) + 2.72 xx 10^(3) h. 7.87 xx 10^(-4) - 2.61 xx 10^(-5)

Calculate the following a. (6.7 xx 10^(5)) xx (4.6 xx 10^(4)) b. (7.6 xx 10^(7)) xx (3.8 xx 10^(-4)) c. (6.8 xx 10^(-3)) xx (5.2 xx 10^(-4)) d. (6.7 xx 10^(5)) / (4.6 xx 10^(4)) e. (7.6 xx 10^(7)) / (3.8 xx 10^(-4)) f. (6.8 xx 10^(-3)) / (3.8 xx 10^(-4)) g. 7.65 xx 10^(2) + 2.72 xx 10^(3) h. 7.87 xx 10^(-4) - 2.61 xx 10^(-5)