Taksiran dan penggantian itu berbeda.

In Indonesian, demonstratives like ini and itu usually come after the noun they modify.

• buku itu = that book / the book
• rumah ini = this house

So:

• taksiran dan penggantian itu is the normal Indonesian order

This is very different from English, where this/that comes before the noun.

In this sentence, itu follows the whole noun phrase, not just a single word.

Most naturally, itu refers to the whole phrase taksiran dan penggantian.

So the structure is basically:

• [taksiran dan penggantian itu] = that estimate and replacement / the estimate and replacement

Because itu comes after the full coordinated phrase, it is normally understood as modifying the entire phrase, not only the second noun.

If a speaker wanted to be extra clear, they could rephrase the sentence, but as written, the usual reading is that itu applies to both.

In Indonesian, berbeda is often taught as meaning different, but grammatically it behaves like a stative predicate. In practical terms, it works a lot like an adjective in English, but Indonesian does not require a separate verb like to be before it.

So:

• Taksiran dan penggantian itu berbeda. = literally something like The estimate and the replacement differ / are different.

Learners often think they need a word for are, but Indonesian does not.

Because Indonesian often uses zero copula with adjectives and many predicate expressions.

In English, you say:

• They are different.

In Indonesian, you simply say:

• Mereka berbeda.

No separate is/am/are is needed.

That is why:

• Taksiran dan penggantian itu berbeda.

is complete and natural without any extra word.

Normally, no. Adalah is generally not used before words like berbeda in standard Indonesian.

So this is natural:

• Taksiran dan penggantian itu berbeda.

But this is generally not the normal choice:

• Taksiran dan penggantian itu adalah berbeda.

If you want to use adalah, you would usually restructure the sentence, for example:

• Taksiran dan penggantian itu adalah dua hal yang berbeda.

So the short rule is:

• before berbeda directly: usually no adalah
• before a noun phrase: adalah is more possible

Taksiran comes from taksir.

The suffix -an often forms a noun. Depending on the root, it can create meanings like:

• the result of an action
• something connected with the action
• an abstract noun

So taksiran is a noun formed from taksir, often meaning something like an estimate, appraisal, or estimated value, depending on context.

This is a very common pattern in Indonesian.

Penggantian comes from the root ganti.

It uses the pattern:

• peN- + root + -an

This pattern often creates a noun referring to:

• a process
• an act
• a result related to the root action

So from ganti (to replace / change) we get:

• penggantian = replacement, substitution, or sometimes compensation, depending on context

This is a very productive Indonesian noun-forming pattern.

Because Indonesian nouns usually do not have to show singular or plural the way English nouns do.

So:

• taksiran can mean estimate or estimates
• penggantian can mean replacement or replacements

The context tells you what is meant.

Sometimes Indonesian uses reduplication to show plurality, but it is not always necessary, especially when the meaning is already clear.

In this sentence, the grammar does not force a singular/plural distinction the way English does.

The normal Indonesian sentence pattern here is:

• subject + predicate

So:

• Taksiran dan penggantian itu = subject
• berbeda = predicate

That gives:

• Taksiran dan penggantian itu berbeda.

Starting with berbeda is possible only in marked or special styles, and it would not be the basic neutral word order learners should use first.

So for ordinary statements, the given order is the natural one.

Yes. In this sentence, dan joins two nouns:

• taksiran
• penggantian

So it forms a coordinated noun phrase:

• taksiran dan penggantian

This works much like English estimate and replacement.

The whole phrase then acts as the subject of the sentence.

Because the two things being compared are already named together as the subject.

So:

• Taksiran dan penggantian itu berbeda.

already means those two things are different from each other.

If you want to state the comparison more explicitly, Indonesian can also say:

• Taksiran itu berbeda dengan penggantian itu.
• Taksiran itu berbeda dari penggantian itu.

Those versions spell out each side of the comparison separately.

So the original sentence is just a more compact way to express the same idea.