No problem, we've got 1791 and 7858 to multiply
1791 × 7858 = 7858 × (1791)
+ 7858 × 1 giving us 7858
+ 7858 × 90 that results in 707220
+ 7858 × 700 that is equal 5500600
+ 7858 × 1000 giving us 7858000

= 14073678
