Convert to Decimal

Question

Convert to Decimal: 3121=3X4³+1X4²+2X4¹+1X4⁰ = 217 _{(base 10)}.

 

Why 1X4⁰ = 4 when 2⁰ = 1?

Answer 1

1*4^0 = 1*1 = 1

 

So

 

3 * 4^3 + 1 * 4^2 + 2 * 4^1 + 1 * 4^0 =

 

3 * 64 + 1 * 16 + 2 * 4 + 1 * 1 =

 

192 + 16 + 8 + 1=

 

208 + 8 + 1=

 

217 (base 10)