Bplus twenty-one equals seventeen

Hello!

B + 21 = 17

B = -4

To get your answer, the only number available must be a negative number, as 21 is already bigger than 17.

Simply by adding 4 to 17 you get 21, so then make that a negative

-4 added to 21 makes a postive number which would be 17

-4 + 21 = 17

Hope this helps!

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