pls help me to solve this question.

Question

thank you very much

binary-decimal conversion

a.101=
b.1100=
c.100110=
d.111111=

decimal binary conversion

a.1216
10

b.2121
10

Answer 1

just like a number like
346₁₀ = 3(10^2) + 4(10^1) + 6(10^0)

a binary number like
c) 100110₂ = 1(2^5) + 0(2^4) + 0(2^3) + 1(2^2) + 1(2^1) + 0(2^0)
= 32 + 0 + 0 + 4 + 2 + 0 = 38

do the others the same way

to do the reverse you will have to know the powers of 2
2^0 = 1
2^1 = 2
2^2 = 4
2^3 = 8
etc.

so to change 1216(base10) to base 2
the largest power of 2 that divides into it is 1024
so
1216 = 1024 + 128 + 64
=1(2^10) + 0(2^9) + 0(2^8) + 1(2^7) + 1(2^6) + 0(2^5) + 0(2^4) + 0(2^3) + 0(2^2) + 0(2^1) + 0(2^0)

= 10011000000₂
do the other one the same way