Place a digit

in each cell

A3
↓ C3
↓D3

L = M + A12

F + G = J + K + 10

A4
↓C4
↓D4
↓D42
B3   B4    
A2
↓C2
↓D2 gg
gg
E→ B12 +D42

Labelled numbers

never start with 0.

↓C42  
B2   g;   A42    
F - G
g; J →
↓ K
    B42
↓D22
   
L + M →          

The labels are the only other

clues that you should need.

  g; L →
↓C22
    ↓D32
A22
↓ M
    g; F →  
A1
↓ C1
↓ D1   B22
↓D12
      g; ↓C32    
B1   ↓C12     g; A32    
A12
↓ 2 x E
    B32 ↓ G      
B12