Abridged Multiplication/Examples/Arbitrary Example
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Example of Abridged Multiplication
Let:
\(\ds x\) | \(=\) | \(\ds 5.6982\) | ||||||||||||
\(\ds y\) | \(=\) | \(\ds 23\) |
Let it be required that $z = x y$ is to be rounded to $2$ decimal places.
Then, when we calculate:
- $z = 5.6982 \times 23$
we can ignore the $4$th decimal place in the partial products of $x y$.
Demonstration
Performing the full multiplication:
5.6982 x 23 ---------- 17.0946 113.9640 ---------- 131.0586 ----------
which rounds to $131.06$.
Ignoring the $4$th decimal place:
5.6982 x 23 ---------- 17.0946 113.9640 ---------- 17.094 -- dropping the 4th decimal place 113.964 ---------- 131.058 ---------
which again rounds to $131.06$.
$\blacksquare$
Sources
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): abridged multiplication
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): abridged multiplication