Four of the following five parts are exactly equal. The number of the part, which is not equal to the other four parts, is your answer.

[1] $o$ 45 × 12 + 60 = 540 + 60 = 600

[2] $o$ 80% of 800 – 40 $= frac{{80 imes 800}}{{100}} - 40$ = 640 – 40 = 600

[3] $o$ $frac{3}{5}$ of 1200 – 150 = $frac{3}{5}$ ×1200 – 150 = 720 – 150 = 570

[4] $o$ $frac{{1260}}{3}$ +180 = 420 + 180 = 600

[5] $o$ $frac{{8640}}{{16}}$ + 60 = 540 + 60 = 600