# what is 999999999999999999 times 9999?

## 999999999999999999 =

10^18 - 1

9999 = 10^4 - 1

999999999999999999 * 9999 =

(10^18 - 1)* (10^4 - 1) =

10^22 - 10^18 - 10^4 + 1

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## To calculate the product of 999999999999999999 and 9999, you can follow these steps:

Step 1: Simplify the multiplication by observing the number of trailing zeros in 9999. Since it is 4, we can remove those zeros by focusing on the remaining digits:

999999999999999999 * 9999 = 999999999999999999 * (9999 * 10000)

Step 2: Next, calculate the product of 9999 and 10000:

9999 * 10000 = 99990000

Step 3: Substitute the result back into the initial equation:

999999999999999999 * 9999 * 10000 = 999999999999999999 * 99990000

Step 4: Perform the multiplication:

999999999999999999 * 99990000 = 999900000000000001 * 10000 - (99990000 - 1)

Step 5: Evaluate the resulting equation:

999900000000000001 * 10000 - (99990000 - 1) = 99990000000000000000 + 10000 - 99990000 + 1

Step 6: Simplify further:

99990000000000000000 + 10000 - 99990000 + 1 = 99990000000000000001

Therefore, the product of 999999999999999999 and 9999 is 99990000000000000001.