Example \[ \begin{aligned} 238 \times 35 & =238 \times(30+5) \\ & =(238 \times 30)+(238 \times 5) \\ & =(238 \times 3 \times 10)+(238 \div 2 \times 10) \\ & =(714 \times 10)+(119 \times 10) \\ & =7140+1190 \\ & =8330 \end{aligned} \] Exerciseica Do these multiplications by breaking down one of the numbers as in the example above: 1. \( 343 \times 25 \) 2. \( 4001 \times 43 \) 3. \( 453 \times 72 \) 4. \( 3200 \times 66 \)

Below are step‐by‐step breakdowns for each multiplication problem, similar to the example given. 1. Multiply 343 by 25   Break 25 into 20 and 5:    343 × 25 = 343 × (20 + 5)       = (343 × 20) + (343 × 5)   Compute each term:    343 × 20 = 343 × 2 × 10 = 686 × 10 = 6860    343 × 5 = 1715   Add the results:    6860 + 1715 = 8575 2. Multiply 4001 by 43   Break 43 into 40 and 3:    4001 × 43 = 4001 × (40 + 3)       = (4001 × 40) + (4001 × 3)   Compute each term:    4001 × 40 = 4001 × 4 × 10 = 16,004 × 10 = 160,040    4001 × 3 = 12,003   Add the results:    160,040 + 12,003 = 172,043 3. Multiply 453 by 72   Break 72 into 70 and 2:    453 × 72 = 453 × (70 + 2)       = (453 × 70) + (453 × 2)   Compute each term:    453 × 70 = 453 × 7 × 10 = 3,171 × 10 = 31,710    453 × 2 = 906   Add the results:    31,710 + 906 = 32,616 4. Multiply 3200 by 66   Break 66 into 60 and 6:    3200 × 66 = 3200 × (60 + 6)       = (3200 × 60) + (3200 × 6)   Compute each term:    3200 × 60 = 3200 × 6 × 10 = 19,200 × 10 = 192,000    3200 × 6 = 19,200   Add the results:    192,000 + 19,200 = 211,200 Thus, the final products are: 1. 343 × 25 = 8575 2. 4001 × 43 = 172,043 3. 453 × 72 = 32,616 4. 3200 × 66 = 211,200