Estimate $87$ to $90$ and $313$ to $300$ and find the product.

$87\times 313$

Estimate the following product:

$9\times 795$

Estimate the following product by rounding off the given numbers to nearest hundred.

$898\times 785$

Estimate $958$ to $1000$, and $387$ to $400$ and find the product:

$958\times 387$

Estimate the following using general rule

$730+998$ 

Estimate the following using general rule.

$796-314$

Estimate the following using general rule:

$12,904+2,888$

Estimate the following using general rule.

$28,292-21,496$

Give a rough estimate (by rounding off to nearest hundreds) and also a closer estimate
(by rounding off to nearest tens)

$439+334+4,317$