Numbers and gender: the 13 to 19 trap

Arabic numbers agree, disagree, or split with the counted noun depending on the range. The compound numbers 13 to 19 are the trap: the units part disagrees in gender with the counted noun, while the tens part agrees.

The canonical example

An apple, تفاحة, is feminine. So fifteen apples is خمس عشرة تفاحة: the units word خمس takes the masculine-looking form (disagreeing with the feminine noun), and عشرة agrees. Writing خمسة عشرة تفاحة, both parts feminine, is the error nearly everyone makes at least weekly.

The quick map

• 1 and 2: agree fully.
• 3 to 10: disagree (reverse polarity), noun in plural genitive.
• 11 and 12: agree in both parts.
• 13 to 19: split, units disagree, tens agree; noun singular accusative.

WriteX classifies these as grammar errors and prints the rule with each fix. For contracts, pair this with the tafqit tool: spelled-out amounts follow the same agreement.