Write the numbers vertically, so the decimal point lines up
Place 0 as a place holder, so that both numbers have same decimal places

	5	9	8	.	5	0
-	0	7	8	.	9	6
				.

Step-1 : `0-6`
Here 0 `<` 6, so we borrow 1 from 5 and add 10 to 0
So 5 becomes `5-1=4` and 0 becomes `0+10=10`
`=10-6`
`=4`

					4	10
	5	9	8	.	5	0
-	0	7	8	.	9	6
				.		4

Step-2 : `4-9`
Here 4 `<` 9, so we borrow 1 from 8 and add 10 to 4
So 8 becomes `8-1=7` and 4 becomes `4+10=14`
`=14-9`
`=5`

					14
			7		4	10
	5	9	8	.	5	0
-	0	7	8	.	9	6
				.	5	4

Step-3 : `7-8`
Here 7 `<` 8, so we borrow 1 from 9 and add 10 to 7
So 9 becomes `9-1=8` and 7 becomes `7+10=17`
`=17-8`
`=9`

			17		14
		8	7		4	10
	5	9	8	.	5	0
-	0	7	8	.	9	6
			9	.	5	4

Step-4 : `8-7`
Here 8 `>` 7, so directly subtract it
`=8-7`
`=1`

			17		14
		8	7		4	10
	5	9	8	.	5	0
-	0	7	8	.	9	6
		1	9	.	5	4

Step-5 : `5-0`
Here 5 `>` 0, so directly subtract it
`=5-0`
`=5`

			17		14
		8	7		4	10
	5	9	8	.	5	0
-	0	7	8	.	9	6
	5	1	9	.	5	4

Write the numbers, so that each digit lines up vertically

	2	0	0	7	8	3
-	1	4	7	3	5	9

Step-1 : `3-9`
Here 3 `<` 9, so we borrow 1 from 8 and add 10 to 3
So 8 becomes `8-1=7` and 3 becomes `3+10=13`
`=13-9`
`=4`

					7	13
	2	0	0	7	8	3
-	1	4	7	3	5	9
						4

Step-2 : `7-5`
Here 7 `>` 5, so directly subtract it
`=7-5`
`=2`

					7	13
	2	0	0	7	8	3
-	1	4	7	3	5	9
					2	4

Step-3 : `7-3`
Here 7 `>` 3, so directly subtract it
`=7-3`
`=4`

					7	13
	2	0	0	7	8	3
-	1	4	7	3	5	9
				4	2	4

Step-4 : `0-7`
Here 0 `<` 7, so we borrow 1 from 0, which takes borrow from 2
So 2 becomes `2-1=1`, 0 becomes `0+10-1=9` and 0 becomes `0+10=10`
`=10-7`
`=3`

		9
	1	10	10		7	13
	2	0	0	7	8	3
-	1	4	7	3	5	9
			3	4	2	4

Step-5 : `9-4`
Here 9 `>` 4, so directly subtract it
`=9-4`
`=5`

		9
	1	10	10		7	13
	2	0	0	7	8	3
-	1	4	7	3	5	9
		5	3	4	2	4

Step-6 : `1-1`
Here 1 `=` 1, so directly subtract it
`=1-1`
`=0`

		9
	1	10	10		7	13
	2	0	0	7	8	3
-	1	4	7	3	5	9
	0	5	3	4	2	4