(5486 + 3578) + 1422 = 5486 + (3578 + 1422) = 5486 + 5000 = 10486
$\snippet{name: op_column, sign: '+', x: 3578, y: 1422, z: 5000}$

4523 + (3788 + 1477) = 3788 + (4523 + 1477) = 3788 + 6000 = 9788
$\snippet{name: op_column, sign: '+', x: 4523, y: 1477, z: 6000}$

(357 + 768 + 589) + (332 + 211 + 643) = (357 + 643) + (211 + 589) + (332 + 768) = 1000 + 800 + 1100 = 1000 + 1900 = 2900
$\snippet{name: op_column, sign: '+', x: 357, y: 643, z: 1000}$
.
$\snippet{name: op_column, sign: '+', x: 211, y: 589, z: 800}$
.
$\snippet{name: op_column, sign: '+', x: 332, y: 768, z: 1100}$

(357 + 298 + 428) + (102 + 572 + 643) = (357 + 643) + (572 + 428) + (102 + 298) = 1000 + 1000 + 400 = 2000 + 400 = 2400
$\snippet{name: op_column, sign: '+', x: 357, y: 643, z: 1000}$
.
$\snippet{name: op_column, sign: '+', x: 572, y: 428, z: 1000}$
.
$\snippet{name: op_column, sign: '+', x: 102, y: 298, z: 400}$

(259 + 728 + 293) + (541 + 607 + 272) = (259 + 541) + (293 + 607) + (728 + 272) = 800 + 900 + 1000 = 1700 + 1000 = 2700
$\snippet{name: op_column, sign: '+', x: 259, y: 541, z: 800}$
.
$\snippet{name: op_column, sign: '+', x: 293, y: 607, z: 900}$
.
$\snippet{name: op_column, sign: '+', x: 728, y: 272, z: 1000}$