Solve the Subtraction Problem: 99 Minus 9

Question

$\begin{aligned} &99 \\ -& \\ &~~9 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

00:00 Solve

00:03 Each time consider a subtraction of 2 digits, and then we'll write

00:06 Let's start by subtracting ones from ones, and write in the ones place

00:09 Write 0 in the missing digits

00:13 Subtract tens from tens, and write in the tens place

00:16 And this is the solution to the question

To solve this problem, let's perform vertical subtraction:

Step 1: Align the numbers 99 and 9 for subtraction.
Step 2: Subtract starting from the rightmost digits: the ones place.
Step 3: $9 - 9 = 0$ in the ones place.
Step 4: Move to the tens place: $9 - 0 = 9$ . (Since we did not borrow any value from the tens place, the 9 remains.)

Thus, the result of the subtraction is $90$ .

Therefore, the solution to the mathematical problem is $90$ , which corresponds to choice 2.