Question

original price of a microscope; $299.50
tax:4%

Answer 1

create two equal fractions x/299.50 = 4/100 multiply 299.50 by 4 which is 1198 and divide it by 100 which is 11.98 round it to 12 and add it to 299.50 which would make the total price 311.50. not 100% sure though