R type, Alu and Logic

Question 1

ADD, ADDI, ADDUI, do what?

Answer 1

add numbers signed, unsigned, and immediate.
ADD R3, R2, R1
R1 + R2 to R3, signed

Question 2

SUB, SUBI, SUBU, SUBUI, do what?

Answer 2

subtract signed, unsigned, immediate,
SUBI R3, R2, #42
R2 - 42 to R3 signed

Question 3

MULT, MULTU, DIV, DIVI, do what?

Answer 3

multiply signed and unsigned floating point numbers
MULT F3, F2, F1
Multiply F2 and F1 to F3

Question 4

AND, ANDI do what?

Answer 4

Logical and also with immediate
ANDI R3, R2, #16
bit 4 from R2 to R3