a = 4.2 10^2 = 420b = 2.1 10^7 = 21,000,000
a + b = 420 + 21,000,000 = 21,000,420a - b = 420 - 21,000,000 = -20,999,580a b = 420 21,000,000 = 8,820,000,000
Therefore:a + b = 21,000,420a - b = -20,999,580a * b = 8,820,000,000
a = 4.2 10^2 = 420
b = 2.1 10^7 = 21,000,000
a + b = 420 + 21,000,000 = 21,000,420
a - b = 420 - 21,000,000 = -20,999,580
a b = 420 21,000,000 = 8,820,000,000
Therefore:
a + b = 21,000,420
a - b = -20,999,580
a * b = 8,820,000,000