To solve this you will be needing to use PEMDAS! Parenthesis exponents multiply divide add subtract! So first parenthesis... 609-78=531 So now we write the problem like this 10*80+531-10^2 Now exponents 10^2 is a exponent so that =10*10 which = 100 So we write it out again like this: 10*80+531-100 Now we need to multiply from left to write So 10*80=800 Re-write it: 800+531-100 So now we need to add from left to write 800+531=1331 1331-100=1231 So your answer is 1231. Does this help any?