Step-by-step explanation:
26×12 = 312
partial products are "strange". but ok, since your teacher wants it that way :
multiply the tens with the tens : 20×10 = 200
multiply the tens with the ones : 20×2 = 40
multiply the ones with the tens : 6×10 = 60
multiply the ones with the ones : 6×2 = 12
--------
312
so, 12 and 40 are correct from the original list, 600 and 2000 are wrong.
how do you do it conceptually ?
26×12 start with the left digit (1),
multiply the left number right to left
6×1 (no carry) 6
2×1 2
26
next digit to the right (2),
also move the result one position
6×2 (carry 1) 2
2×2 (plus carry) 5
52
now we add position related
26
52
---------
2
1 (and carry 1)
3 (2 plus carry)
312
