Note: Given Exp, `= (1/5 ÷ 1/25)/(1/25 ÷ 1/5)` `= (1/5 xx 25)/(1/25 xx 5)` `= 5/(1∕5)` `= (5 xx 5/1)` `= 25`

Note: Given Exp , `=5 - [3/4 + {5/2 - (1/2 + (7 - 6)/42)}]` `= 5 - [3/4 + {5/2 - (1/2 + 1/42)}]` `= 5 - [3/4 + {5/2 - 22/42}]` `= 5 - [3/4 + 83/42]` `= 5 - [229/84]` `= ((420 - 229)/84)` `= 191/84` `= 2 23/84`.

Note: Given Exp . `= (13/4 -4/5 of 5/6)/(13/3 ÷ 1/5 - (3/10 + 106/5)` `= (13/4 - 2/3)/(13/3 ÷ 1/5 - (215/10)` `= (31/12)/(13/3 xx 5) - 215/10` `= ((31∕12))/(65/2 - 43/2)` `= ((31∕12))/(130-129/6)` `= ((31∕12))/((1/6))` `= (31/12 xx 6/1)` `= 31/2` `= 15 1/2`.

Note: Given Exp , `= 48 ÷ 12 xx (9/8 of 4/3 ÷ 3/4 of 2/3)` `= 4 xx (3/2 ÷ 1/2)` `= 4 xx (3/2 xx 2/1)` `= 4 xx 3` `= 12`.

Note: Given Exp , `= {15/2 + 1/2 ÷ 1/2 of 1/4 - 2/5 xx 7/3 ÷ 15/8 of (7/5 - 4/3)]` `= {15/2 + 1/2 ÷ 1/8 - 2/5 xx 7/3 ÷ 15/8 of 1/15}` `= {15/2 + 1/2 ÷ 1/8 - 2/5 xx 7/3 ÷ 1/8}` `= {15/2 + 1/2 xx 8/1 - 2/5 xx 7/3 xx 8/1}` `= {15/2 + 4 - 112/15}` `= ((225 + 120 - 224)/30)` `= 121/30` `= 4 1/30`

Note: Given Exp , `= 459/100 xx 18/10 ÷ 36/10 + 54/10 of 1/9 - 1/5` `= 459/100 xx 18/10 xx 10/36 + 3/5 - 1/5` `= 459/200 + 3/5 - 1/5` `= ((459 + 120 - 40)/200)` `= (539/200)` `= 2.695`.

Note: Given Exp , `= 3/4 ÷ 9/4 of 2/3 - (((3-2)/(6)))/(((3 + 2)/(6))) xx 10/3 + 5/6` `= 3/4 ÷ 3/2 - 1/6 xx 10/3 + 5/6` `= 3/4 xx 2/3 - 2/3 + 5/6` `= (1/2 - 2/3 + 5/6)` `= ((3 - 4 + 5)/6)` `= 4/6` `= 2/3`.

Note: Given Exp, `= (1/2 ÷ 4 + 20)/(1/2 xx 4 + 20)` `= (1/2 xx 1/4 + 20)/(2 + 20)` `= (1/8 + 20)/22` `= (161/8 xx 1/22)` `= 161/176`.

Note: Let,`(17.28 ÷ x)/(3.6 xx 0.2)=2`. Then,`= 17.28/x` `= 1.44x ` or` x= 17.28/1.44` `= 1728/144` `= 12`

Note: `(9^2 xx 18^4)/3^16` `= ((3^2)^2 xx (3 xx 3 xx 2)^4)/3^16` `= (3^4 xx 3^4 xx 3^4 xx 2^4)/3^16` `= (3^12 xx 2^4)/3^16` `= 2^4/3^4` `= 16/81`.