What is the numerical coefficient of the variable $y$y?

$-18y$−18y

What is the numerical coefficient of the variable $k^6$k6?

$3k^6$3k6

What is the numerical coefficient of the variable $k$k?

$-k$−k

What is the numerical coefficient of the variable $t$t?

$\frac{t}{3}$t3

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