The numbers from 1 to 10 are the bases for counting in Portuguese and appear in almost every everyday conversation. They are used for age, quantity, and to form larger numbers. Memorizing these ten numbers allows you to understand simple phrases with quantities. They are also the base for saying hours and dates.

Numbers from 11 to 20 have their own forms that need to be memorized, because they don't always follow a transparent pattern. They appear in ages, dates, times, and quick counting. They are widely used to say how old someone is or to mark days of the month. Learning these numbers makes it easier to understand prices and simple quantities.

Base tens form the numbers from 20 onward and appear in counting, prices, and dates. In Portuguese, we use forms like twenty, thirty, forty, and fifty to build larger numbers. To say 21 to 29, you normally use twenty and the number, as in twenty-one. The same pattern repeats with the other tens up to 90.

Numbers like 21, 22 and 23 are formed with “twenty and” plus the number from 1 to 9. This pattern appears in dates, addresses, and lists. The word “and” links the tens to the units in these cases. The same applies to thirty-one, forty-two, and so on.

“Cem” is used for the exact number 100. For 101 to 199, we use “cento e” plus the value. This contrast appears often in prices, counting items, and references to numbers near 100. The choice between “cem” and “cento” depends on the numeric value and does not change with context.

In dates, the days of the month are usually spoken using cardinal numbers. The day 1 can be said as “one” or “first”, with “first” being common in formal records. The months do not change the number; what changes is how it is read aloud. For years, in Portuguese, the complete number is usually spoken without separating into hundreds.

Ordinals indicate position: first, second, third, fourth and fifth are the most used in everyday life. They appear in addresses, rankings, and instructions. Unlike cardinals, ordinals do not count quantities, but indicate order. In many situations, “first” is the most frequent ordinal.

The ordinals from 6 to 10 follow a pattern with the ending “-o”: sexto, sétimo, oitavo, nono and décimo. They are common in lists, floors, and sequences. In Portuguese, these ordinals rarely change form in casual speech, but they can vary in gender and number in full sentences. The main usage remains to indicate order.

We use cardinals to count things and ordinals to indicate position. The difference appears in sentences like “three students” (quantity) and “third student” (order). In dates, both may appear, but the choice changes the focus of the sentence. In lists and rankings, the ordinal is the expected form.

Ordinals vary in gender to agree with the noun: “primeiro” for masculine and “primeira” for feminine. This rule holds for floors, places in a line, and items in a list. Agreement is mandatory in Portuguese and appears even in the most common ordinals. The plural also exists, but the singular is the most frequent form in basic phrases.

Numbers appear in questions such as age, price, time, and quantity. In Portuguese, it is common to say “how old” with a cardinal and “what time” with a cardinal. In classifications, we use the ordinal to indicate placement. Recognizing these patterns helps understand quick responses in conversations.