Estimate how many times larger 6.1 x 10^7 is than 2.1 x 10^-4

How do i do this activity, is appreciated

The experience c-0.25c can be used to find the cost of an item on sale for 25% off which expression beloit equivalent to c-0.25c

Which number is located at point a on the number line? a number line is shown from negative 10 to 10 with each interval mark on the number line representing one unit. point a is labeled one interval mark to the right of negative 5.