Converting to decimal and hexadecimal

Hello, Tom!

I assume there is a typo in #3 . . .

Quote:

1) Convert $10110001_2$ to decimal

2) Convert $2E_{16}$ to decimal

3) Convert ${\color{red}1}01011111001_2$ to hexadecimal.

I can figure out the conversion,
but am not sure what the sub notation means. . . . . really?

The subscripts represent the bases.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

$1)\;\;10110001_2$ is in base-2.

We have: . $1\!\cdot\!2^7 + 0\!\cdot\!2^6 + 1\!\cdot\!2^5 + 1\!\cdot\!2^4 + 0\!\cdot\!2^3 + 0\!\cdot\!2^2 + 0\!\cdot\!2^1 + 1$

. . . . . . $= \;128 + 0 + 32 + 16 + 0 + 0 + 0 + 1 \;=\;177$

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$2)\;\;2E_{16}$ is in base-16.

We have: . $2\!\cdot\!16^1 + 14\!\cdot\!1 \;=\;46$

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$3)\;\;1010 1111 1001_2$ is in base-2.

To write it in base-16:

. . $\text{we have: }\;\underbrace{1010}_{10} \underbrace{1111}_{15} \underbrace{1001}_{9}$
. . . . . . . . . . $\downarrow \quad\;\, \downarrow \quad\;\;\:\downarrow$
. . . . . . . $= \;\;A\quad\,F\quad\;\;\, 9$

. . . . . . . $= \;\;AF9_{16}$