Find the sum of the first five terms of the following series.1

Find the sum of the first five terms of the following series.
1 + 1 + 1 + .......... + .........
1 × 4 4 × 7 7 × 10

Here , Expression =	1	+	1	+	1	+	1	+	1
	1 × 4		4 × 7		7 × 10		10 × 13		13 × 16

Expression =		1 -	1	+	1	-	1	+	1	-	1	+	1	-	1	+	1	-	1		×	1
			4		4		7		7		10		10		13		13		16			3

Expression =	15	×	1	=	5
	16		3		16

1	+	1	+	1	+ .......... + .........
1 × 4		4 × 7		7 × 10