Question

Make four more such examples.
3. Estimate the following products using general rule:
(a) 578 x 161 (b) 5281 x 3491 ) 1291 x 592 () 9250 x 29​

Answer 1

578×161

Rounding off using general rule

578\Rightarrow600\ \ and\ \ 161\Rightarrow200578⇒600 and 161⇒200

So, 600\times200\ =\ 1,20,000600×200 = 1,20,000

(b) 5,281\times3,4915,281×3,491

Rounding off using general rule

5,281\Rightarrow5,000\ \ and\ \ 3,491\Rightarrow3,0005,281⇒5,000 and 3,491⇒3,000

So, 5,000\times3,000\ =\ 1,50,00,0005,000×3,000 = 1,50,00,000

(c) 1,291\times5921,291×592

Rounding off using general rule

1,291\Rightarrow1,300\ \ and\ \ 592\Rightarrow6001,291⇒1,300 and 592⇒600

So, 1,300\times600\ =\ 7,80,0001,300×600 = 7,80,000

(d) 9,250\times299,250×29

Rounding off using general rule

9,250\Rightarrow9,000\ \ and\ \ 29\Rightarrow309,250⇒9,000 and 29⇒30

So, 9,000\times30\ =\ 2,70,0009,000×30 = 2,70,000

Four more such examples:

Example 1: 391\times561\ \Rightarrow400\times600\ =2,40,000391×561 ⇒400×600 =2,40,000

Example 2: 1,125\times2,307\ \Rightarrow1,100\times2,300\ =\ 25,30,0001,125×2,307 ⇒1,100×2,300 = 25,30,000

Example 3:

54\times3,019\ \Rightarrow50\times3,000\ =\ 1,50,00054×3,019 ⇒50×3,000 = 1,50,000

Example 4:

3,858\times7,682\ \Rightarrow4,000\times8,000\ =\ 3,20,00,0003,858×7,682 ⇒4,000×8,000 = 3,20,00,000