What is -1 represented in bits?

#1

What is -1 represented in bits? I forgot.
And what will be -1<<2 .It was in a lecture. I forgot where it was.

#2

11111111111111111111111111111111

11111111111111111111111111111100
That is equal to -4

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#3

11111111111111111111111111111100
That is equal to -4

How is this -4

#4

It’s Binary signed 2’s complement Whereas when you will calculate it by multiplying with power 2 you will get an answer as
(11111111111111111111111111111100)₂ = (1 × 2³¹) + (1 × 2³⁰) + (1 × 2²⁹) + (1 × 2²⁸) + (1 × 2²⁷) + (1 × 2²⁶) + (1 × 2²⁵) + (1 × 2²⁴) + (1 × 2²³) + (1 × 2²²) + (1 × 2²¹) + (1 × 2²⁰) + (1 × 2¹⁹) + (1 × 2¹⁸) + (1 × 2¹⁷) + (1 × 2¹⁶) + (1 × 2¹⁵) + (1 × 2¹⁴) + (1 × 2¹³) + (1 × 2¹²) + (1 × 2¹¹) + (1 × 2¹⁰) + (1 × 2⁹) + (1 × 2⁸) + (1 × 2⁷) + (1 × 2⁶) + (1 × 2⁵) + (1 × 2⁴) + (1 × 2³) + (1 × 2²) + (0 × 2¹) + (0 × 2⁰) = (4294967292)₁₀
which is decimal number. Both are different.

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#5

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