1428•1829=2611812
After that move to the next digit and write the next result below but before you start add a zero on the answer line, multiply the digits 2·8=16, take the last digit (6) and write it in the answer line, carry the first digit (1) and save it for the next calculation, multiply the digits 2·2= 4, add the carried digit (1) to the previous result 4+1= 5, write the result (5) in the answer line, multiply the digits 2·4=8, write the result (8) in the answer line, multiply the digits 2·1= 2, write the result (2) in the answer line, continue this with every digit and for every row you go down add another zero