I'm gonna guess you're asking if the equation is true or false. Well, the equation is True. 3/10 * 7/10 is 21/100, or in decimal form 0.21. Converting 21/100 to a decimal is 0.21. 0.21 = 0.21. 21/100 = 21/100.
The value closest to zero on the number line is greatest because all of the values are negative which is less than zero. -270 is closer to 0 than the other values.