сӣ

сӣ: thirty

Сӣ раками ҷуфт аст.
Thirty is an even number.
Дарахти чормағз баъди сӣ сол меваи хуб медиҳад.
A walnut tree gives good fruit (produce) after thirty years.

Bonus:
In Tajik, the noun following a number does not take the plural ending (ҳо, он).

сиюм: thirtieth

When a suffix is attached to a word ending in ӣ it is changed to и. Example –
яксаду сию панҷ: one hundred and thirty five

сеяк

сеяк: third

Одам сеяки умрашро дар хоб мегузаронад.
Man spends a third of his life asleep.
Уқёнуси Ором сеяки сатҳи Замин ишғол мекунад.
The Pacific Ocean occupies one third of the surface of Earth.

Bonus:
To say fractions –
аз + denominator + numerator
for example,
2/5, two fifths: аз панҷ ду
3/5, three fifths: аз панҷ се

When the numerator is 1 then the word аз is dropped and the denominator and numerator (1) are joined in one word, for example,
1/3, one third: сеяк
1/4, one quarter: чоряк
1/6, one sixth: шашяк
1/10, one tenth: даҳяк
1/100, one one-hundredth: садяк

рақам

рақам: number

Чор рақами ҷуфт аст.
Four is an even number.
Рақами ҳавлии мо бисту шаш аст.
Our house number is twenty-six.

Bonus:
Synonyms: адад, шумора

рақам мондан: to number
рақами телефон: phone number
рақами ҷуфт: even number
рақами тоқ: odd number

The word рақам can also mean something that has been written.
рақам кардан: to write

дароз

дароз: long

Лаклак паррандаи калонҷусса аст ки, гардану по ва нӯли дароз дорад.
A stork is a large-bodied bird that has a long neck, legs and beak.
Калтакалос, сангпушт ва морҳо муддати дароз бе об зиста метавонанд.
Lizards, tortoises and snakes can live for a long time without water.

Bonus:
Opposite – кӯтоҳ: short

умри дароз: long life
дароз кашидан: to lie down, stretch out
нафаси дароз кашидан: to take a long (deep) breath
дароздум, думдароз: long-tailed
дарозмӯй, мӯйдароз: long-haired

Дароз can also mean “all … long” as in зимистони дароз (all winter long) and рӯзи дароз (all day long).

ҷуфт

ҷуфт: even

Чор рақами ҷуфт аст.
Four is an even number.
Ададҳое, ки ба адади ду каратианд, ададҳои ҷуфт ном доранд.
Numbers which are multiples of the number two are called even numbers.

Bonus:
тоқ: odd

Ҷуфт is also used to mean a pair of something, like як ҷуфт мӯза – a pair of boots.

ҷуфт-ҷуфт: two by two, pair by pair