Please help me on this
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You've got a nice 66 sitting right in the middle of that left side, so wouldn't it be nice if you could get rid of everything else? Well, with a little division and multiplication, we can!
7 7 6 6 5 5 → (7 ÷ 7) × 66 × (5 ÷ 5) = 1 × 66 × 1 = 66