4-One possible performance multiplication enhancement is to do a shift and add instead of an actual multiplication. Since 9 * 6, for example, can be written (2 * 2 * 2 1) * 6, we can calculate 9 *6 by shifting 6 to the left 3 times and then adding 6 to that result. Show the best way to calculate 13 * 7 using shifts and adds/subtracts. Assume both inputs are 8-bit unsigned integers.