Division method for Cube Roots. Having trouble grasping why i get 9.328 instead of 9.321 like the calculator says. I fear there's some missing step in my algorithm, because every time i check the math, i keep getting
2,086,016,000 (about 2 billion) divided by 260,587,200 (about 260 million) and while that borders 7 and 8, i don't see how it comes close to being 1 or 2.
when i multiply 300 x 932 x 932 x 8 i get 2,084,697,600 which fits nicely, even counting the spare change from the remaining two parts of the process.
Which means my process is wrong or ive got a persistent blind spot in my math.
ive highlighted in red where my numbers don't match a calculator. Please help!
Best Answer
When you work out the remainder from the second digit you have one factor of 3 (that digit) too few in the second and third subtrahends. You should render
$81000-(300×9×9×3)-(30×9×3×3)-(3×3×3)=81000-72900-2430-27=5643$
and similarly in the following steps.
As a check, verify that $810000-5643=93^3$.