Definition
Written algorithm
A written algorithm is an ordered set of recorded steps for working out a calculation.
What it means
Instead of doing everything in your head, you write each step in a sensible order. A column method is one kind: ones line up with ones, tens with tens, and any regrouping is recorded. Different written algorithms can be correct if their steps keep the mathematics clear.
Remember it
Think: line up, work through, write down, check.
Example
To add 468 + 257, line up the places. Ones: 8 + 7 = 15, write 5 and regroup 1 ten. Tens: 6 + 5 + 1 = 12, write 2 and regroup 1 hundred. Hundreds: 4 + 2 + 1 = 7. The sum is 725.
Watch for
A final answer or a few unexplained marks are not a written algorithm; the recorded steps must show a method that another person can follow.
Common mix-up
A standard algorithm is one particular widely agreed method. A written algorithm is any valid recorded step-by-step method, so the terms are not always identical.
Exact meaning
A written algorithm is a calculation method written as a fixed sequence of steps, with numbers arranged so place values and operations can be followed and checked.