Estimate the following by rounding off each number to its greatest place:

$9 \times 792$

Estimate the following by rounding off each number to its greatest place:

$87 \times 221$

Estimate the following by rounding off each to the nearest rupee:

$₹5.26 + ₹2.85$

Estimate the following by rounding off each to the nearest rupee:

$₹1.78 + ₹6.82$

Estimate the following by rounding off each to the nearest rupee:

$₹9.07 - ₹5.92$

Estimate the following by rounding off each to the nearest rupee:

$₹5.81 - ₹2.39$

Estimate the following by rounding off each to the nearest rupee:

$₹7.67 - ₹2.05$

Estimate the following by rounding off each to the nearest rupee:

$₹8.05 + ₹4.82$

Estimate the fallowing results:

$6398+17928$