Arrange your numbers with the larger number on top and the smaller number on bottom. Line up the place values of the numbers in columns.
Starting with the ones digit of the bottom number, multiply it by the last digit in the top number
Write the answer below the equals line
If that answer is greater than nine, write the ones place as the answer and carry the tens digit
Proceed right to left. Multiply the ones digit of the bottom number to the next digit to the left in the top number. If you carried a digit, add it to the result and write the answer below the equals line. If you need to carry again, do so.
When you've multiplied the ones digit by every digit in the top number, move to the tens digit in the smaller number.
Multiply as above, but this time write your answers in a new row, shifted one digit place to the left.
When you finish multiplying, draw another answer line below your last row of answer numbers.
Use long addition to add your number columns from right to left, carrying as you normally do for long addition.
ie
1 0 2 4
× 7 6 8
8 1 9 2
+ 6 1 4 4
+ 7 1 6 8
= 7 8 6 4 3 2
