Rule 1: 1. Numbers and statistics in news
Three sizes of number, three behaviours of the counted noun. After 3 to 10 the noun is genitive plural (ثَلَاثَةُ تُجَّارٍ); after 11 to 99 it is accusative singular (سِتٌّ وَأَرْبَعُونَ دَرَجَةً); after 100, 1000, a million and a billion it is genitive singular (مِائَةُ أَلْفِ طُنٍّ, مِلْيَارُ دُولَارٍ). مِلْيُونٌ and مِلْيَارٌ are ordinary nouns and are themselves counted: ثَلَاثَةُ مِلْيَارَاتِ دُولَارٍ. A difference between two totals is introduced by بِـ: زَادَتْ عَلَيْهَا بِأَكْثَرَ مِنْ مِلْيَارٍ exceeded them by more than a billion.
بَلَغَ مَجْمُوعُ الصَّادِرَاتِ سِتَّمِائَةِ أَلْفِ طُنٍّ.
balagha majmūʿu ṣ-ṣādirāti sittamiʾati alfi ṭunnin
The total of exports reached six hundred thousand tons.
سِتَّمِائَةِ accusative as object of بَلَغَ; أَلْفِ genitive after مِائَة; طُنٍّ genitive singular after أَلْف.
كَانَتِ الْوَارِدَاتُ أَكْثَرَ مِنَ الصَّادِرَاتِ بِمِلْيَارِ دُولَارٍ.
kānati l-wāridātu akthara mina ṣ-ṣādirāti bi-milyāri dūlārin
Imports were more than exports by a billion dollars.
بَلَغَتْ دَرَجَةُ الْحَرَارَةِ سِتًّا وَأَرْبَعِينَ دَرَجَةً.
balaghat darajatu l-ḥarārati sittan wa-arbaʿīna darajatan
The temperature reached forty-six degrees.
11–99: accusative singular دَرَجَةً. دَرَجَةٌ is feminine, so the unit is سِتٌّ without ة.
يُبَاعُ الْكِيلُو بِخَمْسَةَ عَشَرَ جُنَيْهًا بَدَلًا مِنْ عَشَرَةِ جُنَيْهَاتٍ.
yubāʿu l-kīlū bi-khamsata ʿashara junayhan badalan min ʿasharati junayhātin
The kilo is sold for fifteen pounds instead of ten pounds.
Price with بِـ; 15 + accusative singular, 10 + genitive plural.
زَادَتِ السَّرِقَاتُ فِي الشَّهْرَيْنِ الْأَخِيرَيْنِ زِيَادَةً كَبِيرَةً.
zādati s-sariqātu fi sh-shahrayni l-akhīrayni ziyādatan kabīratan
Thefts increased greatly in the last two months.
The verbal noun repeated after its verb as an absolute object.