Math 210

Exam #2 review

Cavaet:  Although I try to be comprehensive in these exam reviews, please understand that you are responsible for the material covered since the last exam.  If you notice something that I have missed, please do let me know.

The second hour exam will be Tuesday, March 1, and will cover sections 2.1 - 2.3 and the material on binary, octal, and hexadecimal numbers, binary arithmetic, and two's complement representation.  In particular, be able to

• Be able to convert numbers between base 2, 8, 10, and 16.
• Be able to do binary arithmetic (addition, subtraction, multiplication, and division)
• Be able to describe one's complement, signed-magnitude, excess/bias, and two's complement representation for integers.
• Be able to give (in hexadecimal) the two's complement representation for integers.
• Be able to find the greatest common divisor of two integers, and to find integers a and b so that gcd(m, n) = a*m + b*n
• Be able to write psuedocode for a simple GCD algorithm (direct and recursive)
• Be able to find the multiplicative inverse of a number (modulo some number) when that is possible.  Be able to use that solve an equation a*x=1 mod n
• Be able to encrypt and decrypt messages using addition and multiplication modulo some number n.
• Be able to work with exponents mod n,
• Know Fermat's Little Theorem
• Know the Chinese Remainder Theorem
• Be able to describe RSA encryption

Any questions?  Please ask!  - Bob