In the third grade, I can learn the multiplication of column vertical calculation, and the column vertical calculation is 2 13*4=852.

First, the calculation unit 3*4= 12.

Calculate ten digits 10*4=40, and the result of the previous step is 40+ 12=52.

Calculate 200*4=800 in hundreds, plus the calculation result of the previous step of 800+52=852.