Really?
Ok, think of it this way, a number consist of only 2 digit (with out decimal) add only up to the second digit of another number. Namely
249
10 then subtract them digit by digit.
9 - 0 = 9 (property of 0)
4 - 1 = 3 (definition of successor)
2 have nothing below it as of now
so you get
239
472 is 10 less than 482.
10 less than 1000 = 1000 minus 10 = 990
-10
Prime numbers less than 10 are: 2 3 5 and 7
Subtraction of 10 from 2000 gives the required number. 2000 - 10 = 1990 is 10 less than 2000.
Less than 10 cents.
249*10 = 2490
10% of $249 is $24.90.
-24.9 = -249/10 ( = -249/10 as an improper fraction)
Ten times 249 is 2,490
10 less than 4 = -6
Less than 25 cents.
250
18
10 less than 5
10 less than 449 is 439
24*15 + 249 = 360 + 249 = 609