bài này là ma trân vuông(nxn) nếu bạn cần ma trân nxm thì xem @newborn ở bên dưới(hoặc ở trên) nhé

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1.

uses crt;
var n,i,j:integer;
s:real;
a:array[1..100,1..100] of real;
begin
clrscr;
write('N=');
readln(n);
for i:=1 to n do
for j:=1 to n do
begin
 write('A[',i,':',j,']=');
 readln(a[i,j]);
end;
for i:=1 to n do
for j:=1 to n do
 if a[i,j]>0 then s:=s+a[i,j];
write('tong cac so duong trong ma tran la:',s:4:2);
readln;
end.

2.

uses crt;
var n,i,j:integer;
s:integer;
a:array[1..100,1..100] of integer;
begin
clrscr;
write('N=');
readln(n);
for i:=1 to n do
for j:=1 to n do
begin
 write('A[',i,':',j,']=');
 readln(a[i,j]);
end;
for i:=1 to n do
for j:=1 to n do
 if a[i,j] mod 2<>0 then s:=s+a[i,j];
write('tong cac so le trong ma tran la:',s);
readln;
end.

3.

uses crt;
var n,i,j:integer;
s:real;
a:array[1..100,1..100] of real;
begin
clrscr;
write('N=');
readln(n);
for i:=1 to n do
for j:=1 to n do
begin
 write('A[',i,':',j,']=');
 readln(a[i,j]);
end;
for i:=1 to n do
begin
s:=0;
for j:=1 to n do
 s:=s+a[i,j];
writeln('tong cua cac gia tri tren dong ',i,' la:',s:4:2);
end;
readln;
end.

4.

uses crt;
var n,i,j:integer;
s:real;
a:array[1..100,1..100] of real;
begin
clrscr;
write('N=');
readln(n);
for i:=1 to n do
for j:=1 to n do
begin
 write('A[',i,':',j,']=');
 readln(a[i,j]);

End;

readln(k);
    S=1;
    for j:=1 to m do if a[j,k]<0 then s:=s*a[j,k];
    writeln('Tong gia tri am tren cot k: ',s:0:2);

Readln;

End.

5.

uses crt;
var n,i,j:integer;
s:integer;
a:array[1..100,1..100] of integer;
begin
clrscr;
write('N=');
readln(n);
for i:=1 to n do
for j:=1 to n do
begin
 write('A[',i,':',j,']=');
 readln(a[i,j]);
end;
for i:=1 to n do
for j:=1 to n-1 do
 s:=s+a[i,j];
writeln('tong cua cac gia tri nam tren bien cua ma tran la:',s);
readln;
end.

bài này là ma trận nxm nếu bạn cần ma trận vuông (nxn) thì xem @ThaiHuy ở bên trên nhé.

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uses crt;
var n,m,i,j,k: integer;
    a: array[1..100,1..100] of real;
    sum_duong,volume_le,sum_dong,volume_am_k,sum_bien: real;
begin
clrscr;
    readln(n,m);
    volume_le:=1; sum_duong:=0; sum_dong:=0;
    for i:=1 to n do for j:=1 to m do begin
        read(a[i,j]);
        if a[i,j]>0 then sum_duong:=sum_duong+a[i,j];
        if a[i,j] mod 2 <> 0 then volume_le:=volume_le*a[i,j];
    end;
    writeln('Tong cac so duong: ',sum_duong:0:2);
    writeln('Tich cac so le: ',volume_le:0:2);
    writeln('Tong gia tri cac dong: ');
    for i:=1 to n do begin
        sum_dong:=0;
        for j:=1 to m do sum_dong:=sum_dong+a[i,j];
        writeln(sum_dong);
    end;
    readln(k);
    volume_am_k:=1;
    for j:=1 to m do if a[j,k]<0 then volume_am_k:=volume_am_k*a[j,k];
    writeln('Tong gia tri am tren cot k: ',volume_am_k:0:2);
    sum_bien:=0;
    for j:=1 to m do sum_bien:=sum_bien+a[n,j];
    write('Tong cac gia tri lam tren bien la: ',sum_bien);
    readln
end.