Multiplication algorithm: 5 and 6-digit multiplication (5th grade math)
The multiplication algorithm works the same way with 5 and 6-digit numbers as with shorter numbers. :) First, it makes sense to estimate the final answer, so you can catch gross errors in multiplication.
Here is an example of multiplying a money amount using the standard algorithm. We multiply as if there was no decimal point, and lastly, add the decimal point to the answer. Before multiplying, I estimate the final answer by using rounded numbers.
See also
Example: 2-by-3 digit multiplication — video lesson
The connection between multiplication and division, simple equations, bar models, terminology
Math Mammoth Grade 5 curriculum