$\snippet{name: column_multiplication, x: 28, y: 6}$
 
$\snippet{name: column_multiplication, x: 48, y: 4}$
 
$\snippet{name: column_multiplication, x: 112, y: 8}$
 
$\snippet{name: column_multiplication, x: 125, y: 3}$

230 * 4 − 400 = 520
280 − 490 : 7 = 210
240 * 2 : 6 = 80
180 : 3 : 5 = 12

Вычисления
230 * 4 − 400 = (200 + 30) * 4 − 400 = 200 * 4 + 30 * 4 − 400 = 800 + 120 − 400 = 920 − 400 = 520
280 − 490 : 7 = 280 − 70 = 210
240 * 2 : 6 = ((200 + 40) * 2) : 6 = (200 * 2 + 40 * 2) : 6 = (400 + 80) : 6 = 480 : 6 = 80
180 : 3 : 5 = 60 : 5 = (50 + 10) : 5 = 50 : 5 + 10 : 5 = 10 + 2 = 12