The numbers in the left and right spaces are -2 and -2.
In a diamond problem, the numbers on the left and right sides are typically the two factors, and the top and bottom numbers are the result of multiplying and adding them.
Steps to solve:
The top number is the product of the two side numbers.
The bottom number is the sum of the two side numbers.
In the image you provided, the top number is 4, and the bottom number is -4.
Solution:
To find the two side numbers, think of two numbers that multiply to give 4 (the top) and add up to -4 (the bottom).
The two numbers that work are:
-2 and -2
Multiplying -2 and -2 gives 4 (top).
Adding -2 and -2 gives -4 (bottom).