Step by step solution :

	3	2	1
+	0	4	7

Step-1 :
`=1_8+7_8`
`=1_10+7_10`
`=8_10`
`=8xx1+0`
`=10_8`
`:.` Sum`=0` and carry`=1`

		1
	3	2	1
+	0	4	7
			0

Step-2 :
`=1+2_8+4_8`
`=1+2_10+4_10`
`=7_10`
`=7_8`
`:.` Sum`=7`

		1
	3	2	1
+	0	4	7
		7	0

Step-3 :
`=3_8+0_8`
`=3_10+0_10`
`=3_10`
`=3_8`
`:.` Sum`=3`

		1
	3	2	1
+	0	4	7
	3	7	0

Step by step solution :

	4	0	2	3
+	4	1	6	2

Step-1 :
`=3_8+2_8`
`=3_10+2_10`
`=5_10`
`=5_8`
`:.` Sum`=5`

	4	0	2	3
+	4	1	6	2
				5

Step-2 :
`=2_8+6_8`
`=2_10+6_10`
`=8_10`
`=8xx1+0`
`=10_8`
`:.` Sum`=0` and carry`=1`

		1
	4	0	2	3
+	4	1	6	2
			0	5

Step-3 :
`=1+0_8+1_8`
`=1+0_10+1_10`
`=2_10`
`=2_8`
`:.` Sum`=2`

		1
	4	0	2	3
+	4	1	6	2
		2	0	5

Step-4 :
`=4_8+4_8`
`=4_10+4_10`
`=8_10`
`=8xx1+0`
`=10_8`
`:.` Sum`=0` and carry`=1`

1		1
	4	0	2	3
+	4	1	6	2
	0	2	0	5

Step by step solution :

	1	0	0	7	7
+	0	0	2	5	3

Step-1 :
`=7_8+3_8`
`=7_10+3_10`
`=10_10`
`=8xx1+2`
`=12_8`
`:.` Sum`=2` and carry`=1`

				1
	1	0	0	7	7
+	0	0	2	5	3
					2

Step-2 :
`=1+7_8+5_8`
`=1+7_10+5_10`
`=13_10`
`=8xx1+5`
`=15_8`
`:.` Sum`=5` and carry`=1`

			1	1
	1	0	0	7	7
+	0	0	2	5	3
				5	2

Step-3 :
`=1+0_8+2_8`
`=1+0_10+2_10`
`=3_10`
`=3_8`
`:.` Sum`=3`

			1	1
	1	0	0	7	7
+	0	0	2	5	3
			3	5	2

Step-4 :
`=0_8+0_8`
`=0_10+0_10`
`=0_10`
`=0_8`
`:.` Sum`=0`

			1	1
	1	0	0	7	7
+	0	0	2	5	3
		0	3	5	2

Step-5 :
`=1_8+0_8`
`=1_10+0_10`
`=1_10`
`=1_8`
`:.` Sum`=1`

			1	1
	1	0	0	7	7
+	0	0	2	5	3
	1	0	3	5	2