In the given diagram, each of the 10 circles represents a digit. Fill in the diagram with a valid equality by placing one of the digits from 0 to 9 in each circle, using each digit only once.

## $0 \times O O \times O O O=0 O O$
Let $a, b, c, \ldots, i, j$ be the numbers in the 10 circles, as indicated in the diagram.

$$
(a) \times(b) \times(d)(f)=(g) h(i)
$$

Note that $a, c$, and $f$ cannot be zero, since $0 \times x=0$ for any $x$. However, the product of the three numbers is a four-digit number, so $a b d<10$ and the numbers that appear in $a b d$ are 1, 2, and 3 or 1, 2, and 4. Observe that the second option is impossible, because the minimum product we can obtain in this case is $1 \times 23 \times 456=10488$, so $a b d=6$ and the product is greater than 6000. Neither can $a$ be 2 or 3, because in this case the minimum value of the product is $2 \times 14 \times 356=9968$ and the other products are greater than 10000. Thus, $a=1$. Continuing this analysis, we arrive at the solution given in the diagram.

(1) $\times$ (2)(6) $\times$ (3)(4)(5) $=$ (8)(9)(7)(1)