for loop in if statement, changing value of matrix element depending on its nearby elements

In matrix 'a' i want to convert all its 24 elements to 0 if the middle element has 20 more value than its other 24 elements and leave the middle element as it is. If anyone of the 24 elements does not satisfy the condition, i want it to leave the values of all 25 elements as it is.

clc;
clear;
a= [0.8147    0.0975    0.1576    0.1419    0.6557; 0.9058    0.2785    0.9706    0.4218    0.0357; 0.1270    0.5469    60    0.9157    0.8491; 0.9134    0.9575    0.4854    0.7922    0.9340; 0.6324    0.9649    0.8003    0.9595    0.6787];


if  
    for k=1:1:2
        for l=1:1:2
            a(i,j)-a(i+k,j+l)>20;
            a(i,j)-a(i-k,j-l)>20;
            a(i,j)-a(i+k,j-l)>20;
            a(i,j)-a(i-k,j+l)>20;
            a(i,j)-a(i,j+l)>20;
            a(i,j)-a(i,j-l)>20;
            a(i,j)-a(i-k,j)>20;
            a(i,j)-a(i+k,j)>20;
        end
    end
    a(i,j)=a(i,j);
    
    for k=1:1:2
        for l=1:1:2
            a(i+k,j+l)=0;
            a(i-k,j-l)=0;
            a(i+k,j-l)=0;
            a(i-k,j+l)=0;
            a(i,j+l)=0;
            a(i,j-l)=0;
            a(i-k,j)=0;
            a(i+k,j)=0;
        end
    end

Answer 1

[Walter Roberson]

Subtract the middle number from the entire matrix. If all of the results are less than -20 then the middle was at least 20 more than the other values.

[HEMRAJ PATEL]

no, read the question carefully. Or should i elaborate it.