4. 9 × 81 (1 point)
(9 × 80) + 1 = 721
(9 × 80) – (9 × 1) 711
(9 × 80) + (9 × 1) =729
(9 × 90) – (9 x 1) = 801
To calculate the answer, we can multiply the two numbers: 9 and 81.
9 multiplied by 81 is equal to 729.
So the correct answer is 729.
Among the given options, (9 × 80) + (9 × 1) = 729, so that is the correct calculation.