Note: Let ,`14.3 + 16.78 - x` `=9.009.` Then, `31.08 - x` `=9.009` :.x` = (31.08 - 9.009)` `22.071`

Note: `852.2109 + 106.78 - 59.157` `=985.9909 - 59.157` `=899.8339`

Note: Let, `5463 + 546.3 - 54.63 ÷ x` `= 5999.3` Then,`5463 + 546.3 - (54.63)/x` `= 5999.3` or `6009.3 - (54.63)/x` `= 5999.3` or `54.63/x` `= 6009.3 - 5999.3` or ` 54.63/x` `=10` or x `= 54.63/10` `=5.463`.

Note: Coverting each one of the fiven fraction in decimal form ,we get : `5/6=0.833, 6/8` `0.75, 7/9` `= 0.777, 11/13` `= 0.846` Clearly, `0.75 < 0.777 < 0.833 < 0.846` or `6/8 < 7/9 < 5/6 < 11/13`

Note: Not available

Note: Converting each into decimal form,we get : `11/14 = 0.785,16/19` `= 0.842 & 19/21` `= 0.904`. Clearly , `0.785<0.842<0.904` or `11/14<16/19<19/21`/

Note: We have :`13/16 = 0.8125,15/19` `= 0.7894,17/21` `= 0.8095 & 7/8` `= 0.875`.

Note: `0.000006723` `= (0.00000723 xx 10^6)/10^6` `= 6.723/10^6` `= 6.723 xx 10^-6`

Note: Required decimal `= 1/(60 xx 60)` `= 1/3600` `= .00027`.

Note: `10^k = 0.001125/1.125` `= 1.125/1125` `= (1.125 xx 10^3)/(11125 xx 10^3)` `= 1/10^3` `= 10^-3` :. k `= -3`.