First, subtract 915 − 82:

915 − 82 = 840 − ?

833 = 840 − ?

Find the number that makes the subtraction number sentence true.

840 − ? = 833

Subtract 833 from both sides:

840 − ? − 833 = 833 − 833

7 − ? = 0

Now, find the number that goes in the blank space. Remember, when a number is subtracted from itself, the difference is zero. The number in the blank space must be 7.

The missing number is 7.

First, subtract 407 − 84:

407 − 84 = ? − 94

323 = ? − 94

Find the number that makes the subtraction number sentence true.

? − 94 = 323

Add 94 to both sides:

? − 94 + 94 = 323 + 94

? = 417

The missing number is 417.

First, subtract 941 − 120:

928 − ? = 941 − 120

928 − ? = 821

Subtract 821 from both sides:

928 − ? − 821 = 821 − 821

107 − ? = 0

Now, find the number that goes in the blank space. Remember, when a number is subtracted from itself, the difference is zero. The number in the blank space must be 107.

The missing number is 107.