Estimate each of the following using general rule: 

(a) 730 + 998 (b) 796 – 314 (c) 12,904 +2,888 (d) 28,292 – 21,496

Make ten more such examples of addition, subtraction and estimation of their outcome.

Solution:

We will use " estimation in maths" to solve the given problems: 

a) 

Nearest round off of 730= 700

Nearest round off of 998 = 1000

Therefore,

730+ 998= 700 + 1000 = 1700 

730 + 998 = 1700

b)

Nearest round off of 796= 800

Nearest round off of 314= 300

Therefore, 

796- 314= 800- 300 = 500

796- 314= 500

c)

Nearest round off of 12904 = 13000

Nearest round off of 2888 = 3000

Therefore,

12,904 +2,888 = 13000 + 3000 = 16000

12,904 +2,888 = 16000

d) 

Nearest round off of 28292 = 28000

Nearest round off of 21496 = 21000

Therefore, 

28,292 – 21,496 = 28000- 21000 =  7000

28,292 – 21,496 = 7000

Further, ten more examples of such problem are as follows : 

1. 299 + 249 = 300 + 250 = 550
2. 301 + 201 = 300 + 200 = 500
3. 529 + 349 = 500 + 350 = 850
4. 5160 - 2792 = 5000 - 3000 = 2000
5. 335 + 182 = 300 + 200 = 500 
6. 335 - 182 = 300 - 200 = 100
7. 299 - 249 = 300 - 250 = 50
8. 3841 - 1450 = 4000 - 1000 = 3000
9. 920 - 565  = 900 - 600 = 300
10. 160 + 890 = 200 + 900 = 1100