In Bible 10 Plagues are mentioned.
- Blood (the Nile turns to blood)
- Boils (Skin Diseas)
- Hail Storm
- Death of the firstborn.
- Death of Firstborn.
Now, according to Quran. "10. Death of the firstborn" is not mentioned.
And it seems cruel in first glance, if God kills some innocents (due to the sins of their parents, while Quran says. وَلَا تَكۡسِبُ كُلُّ نَـفۡسٍ اِلَّا عَلَيۡهَاۚ وَلَا تَزِرُ وَازِرَةٌ وِّزۡرَ اُخۡرٰى ۚ (6:164). And every soul earns not [blame] except against itself, and no bearer of burdens will bear the burden of another. ....
But on other way, if we see it in such a way that, Quran says:
"There We prescribed for them (in Torah) a life for a life, an eye for an eye, a nose for a nose, an ear for an ear, a tooth for a tooth, and wounds should have [similar] compensation." (5:45)
As we knew, Pharoah ordered to kill male children of Bani-Israil...
as mentioned in Surah Araf: "[Pharaoh] said, "We will kill their sons and keep their women alive; and indeed, we are subjugators over them." (7:127)
And this Ayat is reminded of similar order his father Pharoah gave, when he was told by his magicians one son will be born from Bani-Israil who will destroy your kingdom....
If we follow the rule,... life for life... then there might be some explanation in it...
(But anyway... it is not mentioned in the Quran)
So, remains 9.
Now, Gnats and Flies seem similar thing. (remains 8)
And after gnats and flies, which causes the diseases, death of livestocks and Boils (skin disease) naturally follows.
(So these two might not be exactly Plagues, but some natural outcome from gnats and flies...)
So remains 6.
Now. This "Darkness" does not seem proper plague...
It could be part of Hail Storm. (Some harsh weather)
So remains 5.
And these 5 are exactly mentioned in Quran. 7:133
"So We sent upon them the flood and locusts and lice and frogs and blood as distinct signs, but they were arrogant and were a criminal people."
Word "Distinct" explains itself... these 5 were especially distinct plagues.
Now as brother mentioned, God says in Quran,
"And We had certainly given Moses nine evident signs, so ask the Children of Israel [about]..." (17:101)
Now, in this Ayat, It does not say: "Plagues" but says Ayat means "Evident Signs".
Five are clearly these ones.
Two mentioned before Ayat 7:130...
"And We certainly seized1 the people of Pharaoh with years of famine and a deficiency in fruits that perhaps they would be reminded."
So, it makes seven.
and Two are those which is mentioned in Surah Araf
"So he [i.e., Moses] threw his staff, and suddenly it was a serpent, manifest." (7:107)
"And he drew out his hand; thereupon it was white [with radiance] for the observers." (7:108)
These are Total 9... Evident Signs.