# Section3.7Exercises

##### 1

Use the “Decoder Ring” in Figure 3.6.2 to perform the following arithmetic. Indicate whether the result is “right” or “wrong”.

1. Unsigned integers: $\hex{1 + 3}$

2. Unsigned integers: $\hex{3 + 4}$

3. Unsigned integers: $\hex{5 + 6}$

4. Signed integers: $\hex{(+1) + (+3)}$

5. Signed integers: $\hex{(-3) - (+3)}$

6. Signed integers: $\hex{(+3) - (+4)}$

##### 2

Add the following pairs of 8-bit numbers (shown in hexadecimal) and indicate whether your result is “right” or “wrong.” First treat them as unsigned values, then as signed values (stored in two's complement format).

1. $\hex{55 + aa}$

2. $\hex{55 + f0}$

3. $\hex{80 + 7b}$

4. $\hex{63 + 7b}$

5. $\hex{0f + ff}$

6. $\hex{80 + 80}$

##### 3

Add the following pairs of 16-bit numbers (shown in hexadecimal) and indicate whether your result is “right” or “wrong.” First treat them as unsigned values, then as signed values (stored in two's complement format).

1. $\hex{1234 + edcc}$

2. $\hex{1234 + fedc}$

3. $\hex{8000 + 8000}$

4. $\hex{0400 + ffff}$

5. $\hex{07d0 + 782f}$

6. $\hex{8000 + ffff}$