1. The problem is to multiply 432 by 61 using lattice multiplication. 2. Lattice multiplication is a method that breaks the multiplication into smaller parts using a grid. 3. Write the numbers 432 and 61 on the top and right side of a grid respectively. 4. Multiply each digit of 432 by each digit of 61 and write the results in the corresponding cells, splitting tens and units diagonally. 5. For example, multiply 4 by 6 to get 24, write 2 in the top triangle and 4 in the bottom triangle of the cell. 6. Repeat for all digit pairs: 4x1=4 (write 0 and 4), 3x6=18 (1 and 8), 3x1=3 (0 and 3), 2x6=12 (1 and 2), 2x1=2 (0 and 2). 7. Sum the numbers along the diagonals starting from the bottom right, carrying over if needed. 8. The sums are: rightmost diagonal 2, next diagonal 4+1+3=8, next 2+8+0=10 (write 0 carry 1), next 1+4+1=6, leftmost 0+2=2. 9. Reading the sums from left to right gives the final product: 26352. 10. Therefore, $432 \times 61 = 26352$.