7961 * 84 = 668724
$\snippet{name: column_multiplication, x: 7961, y: 84}$
 
4524 * 56 = 253344
$\snippet{name: column_multiplication, x: 4524, y: 56}$
 
17356 * 23 = 399188
$\snippet{name: column_multiplication, x: 17356, y: 23}$
 
23815 * 16 = 381040
$\snippet{name: column_multiplication, x: 23815, y: 16}$
 
16440 : 60 * 40 + 8888 = 274 * 40 + 8888 = 10960 + 8888 = 19848
1) $\snippet{name: long_division, x: 16440, y: 60}$;
2) $\snippet{name: op_column, sign: '×', x: '274   ', y: '40', z: '10960 '}$;
3) $\snippet{name: op_column, sign: '+', x: '10960', y: '8888', z: '19848'}$.
 
15260 : 70 * 60 − 7777 = 218 * 60 − 7777 = 13080 − 7777 = 5303
1) $\snippet{name: long_division, x: 15260, y: 70}$;
2) $\snippet{name: op_column, sign: '×', x: '218   ', y: '60', z: '13080 '}$;
3) $\snippet{name: op_column, sign: '-', x: '13080', y: '7777', z: '5303'}$.