What is the answer to page 4.19 of bridge to algebra?

A symbol representing a value that does not change? How do I make a valid question? What is the standard notation for 0.0029? What is the simplest ratio form 33 to 55? How many degrees are the angles of a regular hexagon? What is 0.21 rounded to the nearest whole number? What square roots lie between 5 and 6? Are all rhobuses squers? What is 3473 in Roman numerals? What is 72 less than 81? What are the Steps involved in construction of frequency distribution table? How many ft is 45 inches? What is log10 - log 8? What is the antonym for ascend the stairs? What number multiplies to 138 but adds to 28? Is 0.408 greater less than or equal to 0.51? What is the order of magnitude of the number 889432? What is 1981 written in roman numeral numbers? How would the number 98160000000000000 appear in the newspaper? What is the LCM of 1 2 5 7 8 9 and 10?