Final answer:
The empty boxes in the multiplication of 0.53 and 0.67 should be filled with the number 1 to correctly represent the product as 0.3551.
Step-by-step explanation:
The number that should go in the empty boxes to complete the calculation for finding the product of 0.53 and 0.67 is 1. The partial products method of multiplication shows that 0.53 times 0.67 results in two partial products: 371 (0.53 × 0.7) and 106 (0.53 × 0.06) which add up to 3551 when we consider their place values correctly. Therefore, the boxes in the expression should be filled with a 1 to represent the units place of the final answer, 0.3551, correctly.