Umak je blag, pa ga i djeca rado jedu.

Yes. Blag is an adjective, and it has to agree with umak in gender, number, and case.

• umak = masculine, singular, nominative
• so the adjective is blag = masculine, singular, nominative

If the noun were feminine or neuter, the adjective form would change:

• juha je blaga
• jelo je blago

Here blag usually means mild in the sense of flavor, especially not too strong or spicy.

In this sentence, blag most naturally means mild.

For food, that usually suggests:

• not spicy
• not harsh
• easy to eat

Depending on context, English might translate it as:

• mild
• gentle in flavor
• sometimes not too strong

It does not automatically mean bland in a negative sense. It can simply mean the sauce is suitable even for children because the taste is not too intense.

Ga is the short pronoun meaning him/it in the accusative singular.

In this sentence, it stands for umak:

• Umak je blag, pa ga i djeca rado jedu.
• literally: The sauce is mild, so even children gladly eat it.

Instead of repeating umak, Croatian often uses a pronoun:

• Umak je blag, pa djeca rado jedu umak. → possible, but more repetitive
• Umak je blag, pa ga i djeca rado jedu. → more natural

So ga = it.

Because umak is a masculine singular noun, and the short accusative pronoun for masculine singular is ga.

Croatian pronouns do not work exactly like English he/him/it. The form depends mainly on grammar:

• gender
• number
• case

So even though umak is not a person, the pronoun is still ga because it is masculine singular accusative.

Here pa means something like:

• so
• and so
• therefore
• sometimes just a natural linking and

In this sentence, it connects the two ideas with a sense of result:

• The sauce is mild, so even children gladly eat it.

It is not exactly the same as jer (because).
Compare:

• Umak je blag, pa ga i djeca rado jedu. = The sauce is mild, so even children eat it gladly.
• Djeca ga rado jedu jer je umak blag. = Children gladly eat it because the sauce is mild.

Here i does not mean and. It means also or even.

So:

• i djeca = even children / children too

In this sentence, it adds emphasis:

• the sauce is so mild that even children like eating it

This is a very common use of i in Croatian.

Good question. Djeca means children, and it takes a plural verb:

• djeca jedu = children eat

Even though djeca ends in -a, it is not treated like a normal feminine singular noun here. It is a plural meaning word and uses plural agreement.

Compare:

• dijete jede = the child eats
• djeca jedu = the children eat

This is something learners simply have to get used to.

Rado is an adverb meaning:

• gladly
• willingly
• with pleasure

So rado jedu means:

• they gladly eat
• they like eating
• they willingly eat

This is a very common Croatian way to express liking an action.

For example:

• Rado čitam. = I like reading / I gladly read.
• Ona rado kuha. = She likes cooking.

Because ga is a clitic, a short unstressed word. In Croatian, clitics usually go very near the beginning of the clause, in a fixed position.

So:

• pa ga i djeca rado jedu sounds natural
• pa i djeca rado jedu ga sounds wrong

A simple learner-friendly rule is:

• short pronouns like ga, mu, se, je often come early in the clause

The rest of the sentence is arranged for emphasis:

• i djeca highlights even children
• rado modifies jedi/jedu and often comes before the verb

Usually, if you want to keep the meaning eat it, the pronoun is helpful and natural.

• Umak je blag, pa ga i djeca rado jedu. = clear and natural
• Umak je blag, pa i djeca rado jedu. = sounds incomplete unless the object is already extremely obvious from context

So in this sentence, ga is there to make it clear that they eat the sauce / it.

Yes. Jedu is the 3rd person plural present form of jesti (to eat).

A few present-tense forms are:

• jedem = I eat
• jedeš = you eat
• jede = he/she/it eats
• jedemo = we eat
• jedete = you (plural/formal) eat
• jedu = they eat

Since djeca is plural in meaning and agreement, the verb is jadu? No — the correct form is jedu.

It is very natural. It sounds like normal everyday Croatian.

The sentence has several features that are very typical:

• adjective agreement: umak je blag
• result-linking with pa
• pronoun instead of repeating the noun: ga
• emphasis with i = even
• adverb rado
• plural agreement with djeca jedu

So this is a very good example of real, idiomatic Croatian.