`\frac{1}{1.2} + \frac{1}{2.3} + \frac{1}{3.4}+ \frac{1}{4.5}`
`= 1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + 1/4 - 1/5`
`= 1 - 1/5`
`= 4/5`
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`\frac{2}{1.2} + \frac{2}{2.3}+ \frac{2}{3.4}+ \frac{2}{4.5}`
`= 2 -2/2 + 2/2 - 2/3 + 2/3 - 2/4 + 2/4 - 2/5`
`= 2 - 2/5`
`=8/5`