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`=</2`

`+Expr1` `=<`

`+Expr2`

Succeeds if the result of evaluating `Expr1` is *less
than or equal* to the result of evaluating `Expr2`.

`Expr1`*expr*, must be ground`Expr2`*expr*, must be ground

Evaluates `Expr1` and `Expr2` as arithmetic expressions and
compares the results.

Arithmetic errors (see ref-ari-exc).

| ?-42 =< 42.yes

| ?-"b" =< "a".no

Note that the symbol ‘`=<`’ is used here
rather than ‘`<=`’, which is used in some other languages. One way to
remember this is that the inequality symbols in Prolog are the ones
that cannot be thought of as looking like arrows. The ‘`<`’ or ‘`>`’
always points at the ‘`=`’.

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