Maths exercise Solve this fast

While scuba diving, rajeev dove to a depth of 12.6 feet below the surface of the water and then descended another 8.7 feet. what expression can be used to find rajeev's new position? 12.6 – 8.7 –12.6 – 8.7 –12.6 – (–8.7) 12.6 – (–8.7)

School has 204 sixth grade students. if the sixth grade is 30% of the total school, how many students are in the middle school?

Abacteria population is tripling every hour. by what factor does the population change in 1/2 hour? select all that apply