a. 1057= 1× 10？ +5× 10+7× 1

b. 1 10 10 1= 1×2^5+ 1×2^4+0×2？ + 1×2? +0×2? + 1×2?

c.C× 16？ +3× 16? +B× 16？ +2× 16? +a× 16^4+ 1× 16^5= 12× 16？ +3× 16? + 1 1× 16? +2× 16? + 10× 16^4+ 1× 16^5

Figure 2 is not clear.

Figure 3:

a. 1 10 10= 1×2^4+ 1×2？ +0×2? + 1×2? +0×2? = 16+8+2=26

b. 10 10 1 1 1= 1×2^6+0×2^5+ 1×2^4+0×2？ + 1×2? + 1×2? + 1×2? =64+ 16+4+2+ 1=87

A. 18A = 1100010 (take18a as1,8, a three numbers, and then respectively correspond to the binary numbers of these three numbers).

B ABC =10101kloc-0/1100 (method as above).

Figure 4:

A.27 =1101(when 27 is divided by 2 until the result is 0, the remainder is recorded from bottom to top).

B.350 =101011165438 (method as above).

a.59=3B

b.428= 1AC