i understand your question in two cases and i explain according to that.

Case 1 :
if your Taxable income is 20000 then your TAX is – 10 % of 20000 = 2000 R.S

Case 2 :
if your Tax is 20000, means your taxable income is 2 Lac(20000*100/10)

1) if you want to save Tax or reduce your tax to zero under 80C Scheme (the saving upto 1Lac) you can save 10000(10%of 1Lac).
2) if you stay in Rented House you can save Tax by showing Rent Receipt. “this Rent or HRA excemption NOT COME in 80C tax saving scheme”

if Case 1 apply to you then you can show the rent Receipt Exemption or PPF account savings
if Case 2 is apply then it is difficult to much saving as more tax in case 2 , you can maximum save 10000(under 80C but for that you have to invest 1Lac is LIC/PPF/MF etc).
You can Show the Rent Receipt .
Rent Exemption calculation

suppose you pay Rent of 7500 per month then
minimum value of 3 case given below will applicable
1) HRA received
2) 40% of Salary given in Rent(50% case for Metro Cities)
3) Rent_Paid – (10 % of Basic_Salary).

mostly in cases the minimum value come in case 3 so this is applicable

suppose your basic salary is 15000( 10 % of 15000=1500)
if rent paid 7500 then 7500 – 1500 = 6000

total rent yealy given =6000 X 12 = 72000
now 10 % of 6000 = 600 per month.
or 10% of 72000 = 7200 Yearly

and this calculate like this suppose your taxable income is 2Lac then 2Lac -72000 = 128000
now your Tax is = 128000*10/100 = 12800

if you also Spent 1Lac in 80C then =128000 – 100000 =28000
Now your Tax is = 28000 X 10 /100 =2800 R.S.

i understand your question in two cases and i explain according to that.

Case 1 :

if your Taxable income is 20000 then your TAX is – 10 % of 20000 = 2000 R.S

Case 2 :

if your Tax is 20000, means your taxable income is 2 Lac(20000*100/10)

1) if you want to save Tax or reduce your tax to zero under 80C Scheme (the saving upto 1Lac) you can save 10000(10%of 1Lac).

2) if you stay in Rented House you can save Tax by showing Rent Receipt. “this Rent or HRA excemption NOT COME in 80C tax saving scheme”

if Case 1 apply to you then you can show the rent Receipt Exemption or PPF account savings

if Case 2 is apply then it is difficult to much saving as more tax in case 2 , you can maximum save 10000(under 80C but for that you have to invest 1Lac is LIC/PPF/MF etc).

You can Show the Rent Receipt .

Rent Exemption calculation

suppose you pay Rent of 7500 per month then

minimum value of 3 case given below will applicable

1) HRA received

2) 40% of Salary given in Rent(50% case for Metro Cities)

3) Rent_Paid – (10 % of Basic_Salary).

mostly in cases the minimum value come in case 3 so this is applicable

suppose your basic salary is 15000( 10 % of 15000=1500)

if rent paid 7500 then 7500 – 1500 = 6000

total rent yealy given =6000 X 12 = 72000

now 10 % of 6000 = 600 per month.

or 10% of 72000 = 7200 Yearly

and this calculate like this suppose your taxable income is 2Lac then 2Lac -72000 = 128000

now your Tax is = 128000*10/100 = 12800

if you also Spent 1Lac in 80C then =128000 – 100000 =28000

Now your Tax is = 28000 X 10 /100 =2800 R.S.