Combining "Em" with Demonstratives

The preposition emin Slow audio Play audio Preposition can be combined with variable and invariable demonstratives to form a number of very useful contractions.
Remember that all the same rules for demonstratives remain valid when they appear in the following contractions.

Em + Variable Demonstratives

Relative Position	Demonstrative	Contraction
Near the speaker:	estethis Slow audio Play audio Demonstratives, Singular, Masculine estathis Slow audio Play audio Demonstratives, Singular, Feminine estesthese Slow audio Play audio Demonstratives, Plural, Masculine estasthese Slow audio Play audio Demonstratives, Plural, Feminine	neste Slow audio Play audio Demonstratives, Contractions, Masculine nesta Slow audio Play audio Demonstratives, Contractions, Singular, Feminine nestes Slow audio Play audio Demonstratives, Contractions, Plural, Masculine nestas Slow audio Play audio Demonstratives, Contractions, Plural, Feminine
Near the listener:	essethat Slow audio Play audio Demonstratives, Singular, Masculine essathat Slow audio Play audio Demonstratives, Singular, Feminine essesthose Slow audio Play audio Demonstratives, Plural, Masculine essasthose Slow audio Play audio Demonstratives, Plural, Feminine	nesse Slow audio Play audio Demonstratives, Contractions, Singular, Masculine nessa Slow audio Play audio Demonstratives, Contractions, Singular, Feminine nesses Slow audio Play audio Demonstratives, Contractions, Plural, Masculine nessas Slow audio Play audio Demonstratives, Contractions, Plural, Feminine
Away from both:	aquelethat Slow audio Play audio Demonstratives, Singular, Masculine aquelathat Slow audio Play audio Demonstratives, Singular, Feminine aquelesthose Slow audio Play audio Demonstratives, Plural, Masculine aquelasthose Slow audio Play audio Demonstratives, Plural, Feminine	naquele Slow audio Play audio Demonstratives, Contractions, Singular, Masculine naquela Slow audio Play audio Demonstratives, Contractions, Singular, Feminine naqueles Slow audio Play audio Demonstratives, Contractions, Plural, Masculine naquelas Slow audio Play audio Demonstratives, Contractions, Plural, Feminine

These contractions can be used to indicate positions, movement or time, to identify something more clearly, and so on.
Eu vou neste carro naquela direçãoI'll go in this car in that direction Slow audio Play audio
Nada pode ser feito nesses casosNothing can be done in those cases Slow audio Play audio
Muitas coisas eram diferentes naqueles temposMany things were different in those times Slow audio Play audio

Em + Invariable Demonstratives

Similarly, em combines with the invariable demonstratives (isto, isso, and aquilo) to form:

• Near the speaker: nistoin this Slow audio Play audio Demonstratives, Contractions
• Near the listener: nissoin that Slow audio Play audio Demonstratives, Contractions
• Away from both: naquiloin that Slow audio Play audio Demonstratives, Contractions

Remember that contractions built from invariable demonstrative pronouns, as expected, can never be followed by nouns, and are usually used to describe things that are unknown or more abstract:
Não me vou envolver nistoI won't get involved in this Slow audio Play audio