For thousands of years, humans have used mathematics for the most daily activities of life, from counting an apple to distances. It must be borne in mind that in life everything is done by proportions, and mathematics is in charge of it, hence the importance of numbers.
If there is something that has always been said, it is that it does not matter in the country you are in because you will always understand the numbers since they are a universal language. You may not understand the lyrics, but the spelling of the numbers is the same in Spain, China or London, to give several examples. So it has always been very important to know how numbers are written with letters and how numbers are written with numerical spelling.
In addition, it must also be taken into account that numbers can be of various forms. Or natural, that is, without decimals, such as the number of inhabitants of a city; decimals, such as the distance between two points; or they can also be Roman, which in this case is written differently, since it is another system.
Natural numbers
The natural numbers are those that are used to count objects or whole quantities, that is, without dividing one of them. The number of bottles on a table is a natural number, different from the amount of water in them. The natural numbers are countable and help us to add, subtract or play with quantities in a simple way.
Decimal number
Decimal numbers are those that are not integers, that is, they do not have complete amounts. The number of liters in so many bottles can result in a decimal number, however the number of bottles cannot. Decimal numbers are characterized by having a comma and behind that comma, that is, to the right of it, other numbers continue and those are the decimals.
Roman numerals
Roman numerals is a numbering system that, as its name suggests, was used by the Romans and consists of using capital letters to write the numbers. Its characteristic is that to form the final number, each of the numbers had to be added from the left, since putting a number in front of or after another means that you subtract or add, hence starting from the left. To put one, an I is used and you can put a maximum of three in a row, since to name five there is V and four is reached by subtracting a number from five, that is, instead of putting the I behind it put it in front :IV. And so with the X you made ten, with the L fifty, so forty is XL or what is the same, from fifty, which is the L, subtract the ten, which is the X. For the hundred there was the C, for the five hundred the D and for a thousand the M. And with these few letters in the Roman system all numbers that were natural or integers could be written. Always keeping in mind that you start from the left and that depending on whether the numbers go to the left or right of others they serve to add or subtract, so the number 1243 would be MCCXLIII (the M for a thousand; the two Cs to add the two hundred; to make forty we have to put fifty minus ten, so it is XL; and to make three, three III in a row). to make forty we have to put fifty minus ten, so it is XL; and to do the three, three IIIs in a row). to make forty we have to put fifty minus ten, so it is XL; and to do the three, three IIIs in a row).
The biggest problem that exists when writing numbers lies in separating them when adding units, tens, hundreds and so on. What this means is that when there is only one unit, from 0 to 9 there is no problem, when there are dozens, that is, from 10 to 99, the complications begin and then from 100 everything is to follow the first guidelines but knowing that we are in the hundreds, of a hundred, and not in the tens, of ten, that this refers to the number of numbers it has.
It is very important to know how to write numbers with letters, because in many school exercises you have to know if they give you a quantity written with numerical spelling, how it is translated into letters. The simple thing about Spanish is that all the numbers are written just as they are pronounced, in a different way than in other languages such as English where you see 1 written but say ‘one’.
If we start from the beginning it would be 0 and if we pronounce it in Spanish we will only have to write the four letters that we pronounce, that is, zero. With 1 it would be one; with the 2, two; and so on up to 9, which would be nine. From here the units end and the tens begin, which is nothing more than the union of the highest figures of units. The 10 would not be a zero, as one might think, because it is not a sum with the symbol +, but both numbers have been joined, so after the nine, comes the ten. The same would happen with 11, it is not one one, but eleven. Another way of thinking that they can be written would be to say, if 10 is a ten, it would be tenth, tenth, tenth… and so on, but that way of writing the numbers is wrong.
When we reach 20-something another problem arises and that is that many people between one figure and another want to link it, that is, the y, but this is not the case. If we see the number 23 written, it is not a two three, nor a twenty three, no. It would be twenty-three all together because we are not separating it according to units (which would be three) and tens (which would be twenty). With 30 (thirty), 40 (forty), 50 (fifty) and so on.
When we go past twenty-nine (29) the links for the following numbers do begin. This means that if 30 is written thirty, 33 will be the sum of thirty and three, so it is thirty-three, in this case the nexus is used. But this rule never works for the 20-29.
Knowing this, for 40, 50, 60, 70, 80 and 90 the same thing happens as with 30. Bearing in mind that we already know how to write from 0 to 9 and that 30 is thirty, 40 is forty, 50 is fifty, 60 is sixty, 70 is seventy, 80 is eighty and 90 is ninety, we have everything ready, we just have to add. If we use 88 as an example, we know that the ten is 80 and we have said that it is written eighty, and that the unit is 8, which we have learned is eight, so if we join by means of a nexus we have that 88 is written eighty-eight. With another example we show that it is a universal rule, if we have 53, we know that the ten is 50 which is fifty and that the unit is 3 which is three, we put the nexus and we know that 53 is written fifty-three.
You only have to learn how to write the numbers from 0 to 9 and how to write the tens from 10 to 90. Knowing that we have everything done.
If we go to the level of hundreds, that is to say 100, we have to learn something new and that is how to write the number 100 and since it is a hundred, we leave it at one hundred. From 101 to 109 is the same as from 0 to 9, we know that 100 is one hundred and that 8 is eight and that until it exceeds 30, we must not use the nexus, so 108 would be one hundred and eight, yes, separating the words.
If we take a number between 100 and 999, that is, three digits, the same thing will always happen using the learned pattern. One more thing should be known, and that is that it counts as hundreds, the word ‘hundreds’ will always go before the number of times that hundred is repeated. For example, if it is 400, how many times do we repeat the hundred?, 4, so it is four hundred. And if it were 401, then we do have to separate the number and it would be four hundred and one. If we have 500 it would not be five hundred as we would deduce if we follow the pattern, but it would be five hundred, this is the only change, for the rest it remains the same. So if we see that it is 567 it would be five hundred (500), sixty (60) and seven (7): five hundred sixty-seven.
If we go to a thousand, that is to say 1,000, we must know one more detail and that is that instead of being hundreds there are ‘thousands’, so there will always be a ‘thousand’ behind the number of times that is repeated. Which means that 4,000 is four thousand, and here with 5,000 it would be five thousand. As a result of this, we only have to follow the rules that we know from 0-9 from 10 to 99 and from 100 to 999. So if we have the number 6,892 we would have to think that the thousand is six (6) so that is six thousand; that the hundred is 800 so it is eight hundreds; that the ten is 90 that is ninety; and that the unit is a 2, which is two, so if we put it all together, the result would be six thousand eight hundred and ninety-two.
The difficult thing is to make the first transfers from numerical spelling to writing, but from the first numbers everything is much easier. The larger the figure on the left, we must add the rules that we have learned from scratch, but otherwise everything is very simple.
To make things easier for you, what you could do is write the basic rules on a piece of paper, that is, how to write 0-9, how to say 10, 20… and then the same with 100, 200… and so on. You will only have to see if it is a single unit, or there are tens and hundreds and know what to look for on the paper that you write.
At first it may be a little difficult for you, but with some practice you will realize that it is very simple, you may get confused with the five, because there are times that it changes since it is not regular when it is written because sometimes it is five hundred and not five hundred, and take into account when the link is used and when they are written together and separately, but they are very basic rules that with a couple of examples that you follow you will notice that it is much easier than you thought at first and if you have doubts, you can ask someone and little by little you will loosen up to know how numbers are written.