<h2><em><u>Solution</u></em> : </h2>
let the last number be x
we know,

So,





therefore, the last number is 10.
Step-by-step explanation:
square root 15 = irrational
square root 16 = 4 = rational
square root 21 = irrational
square root 22 = irrational
42 - (-25) = 42 + 27 = 69
33 - (-77) = 33 + 77 = 110
44 + (-18) = 44 - 18 = 26
NOT SHUUUUUUUUURRRRREEEEEEE