The following sentence isn't grammatically correct and I don't know why ?
We should spend more money on education and health and fewer on new technology.
Could anyone help ?
"Money" is uncountable, so the correct sentence is:
"We should spend more money on education and health and less on new technology."
Conversely, the same idea can be expressed as
We should spend more dollars on education and fewer on new technology.
More is acceptable for both countable and not countable.
More beans and more water.
But
Fewer beans and less water
We say less money not fewer money because it is a mass noun (uncountable). The noun money can also be omitted when it is inferred by the verb spend.
But units of money such as euros, dollars, coins, cents, etc. are countable, and it is considered grammatically more acceptable to use few/fewer. The unit of money cannot be omitted in this case
In English grammar, some things are seen as a whole or mass. These are called uncountable nouns, because they cannot be separated or counted.
Other common uncountable nouns include:
accommodation, baggage, homework, knowledge, money, permission, research, traffic, travel.
Cambridge Dictionaries