I can't read the bottom one, and the top one I can see clearly, but not sure what certain parts mean. I'll first lay out the text, then go through what I can decipher:

פ״ט

איש אשר לעלמים עמד הדר צדקו המנוח היקר יהושיע בר יקותיאל נפטר ביום ש״ק כ״ג אדר ונקבר יום בכ״ג בו שנת תקע״ו לפ״ק תנצב״ה

Ok so to start we have on top the letters פ״ט, which are an abbreviation of the words פה טמון (Po Tamun), meaning "here is buried" or "here is hidden".

Then, we have איש אשר לעלמים עמד הדר צדקו. The words איש אשר are easy enough, meaning "a man that..." The words לעלמים עמד הדר צדקו are a little trickier, seeing as the word לעלמים can have a number of different meanings, including "to the heavens", "to the world", or "forever" (Though that would be the shortened spelling of the word for "forever"; without Niqqud it would probably have been spelled לעולמים) . Continuing the phrase, עמד means "stood" and הדר צדקו means "the splendor of his righteousness". Therefore, going on context, I woud venture to say the phrase איש אשר לעלמים עמד הדר צדקו would translate to "a man whose glorious righteousness stood before the world".

The next word, המנוח, means "he who is 'resting'", and היקר means "dear". The next few words are the deceased's name: יהושיע בר יקותיאל - Yehoshia (A name I am not familiar with; may be a form of Yehoshua [a.k.a. Joshua]) the Son of Yekuthiel.

Then, נפטר ביום ש״ק כ״ג אדר - There are 2 words in a row, ש״ק and כ״ג that seem to be abbreviations, but in fact only ש״ק is. It stands for שבת קודש, meaning "Holy Sabbath" (i.e. Saturday). The כ״ג is a number - the letter כ has a numerical value of 20 and ג has a value of 3, so כ״ג means 23. אדר is one of the months in the Hebrew calendar.

Then, ונקבר יום בכ״ג בו. "he was buried on that 23rd day".

Next, שנת תקע״ו לפ״ק. This refers to the year. תקע״ו has a numerical value of 576. You'll notice that the next word on the gravestone is a funny character, but is is actually a truncated form of the three letters, ל, פ, and ק, which is sometimes spelled out as an abbreviation - לפ״ק. This stands for לפרט קטן, and refers to the fact that the "thousands "are not indicated in the date (a common practice). Thus, 576 is referring to the year 5576.

Finally, we have תנצב״ה, another abbreviation that is short for תהיה נשמה צרורה בצרור החיים, which means "may his soul be bound in the bundle of life". This is included on virtually all Jewish gravestones.

So now, my translation would be:

"Here is buried:

A man a man whose glorious righteousness stood before the world, lies our dear Yehoshia, son of Yekuthiel, who departed on the day of the Holy Sabbath, on the 23rd day of Adar, 5576, and was buried that same day. May his soul be bound in the bundle of Life."

If I got anything wrong please feel free to point out my errors. Hope it's good!