Use the numbers 1-9 (each number can only be used once) to form a three digit minus three digit formula
There are many possibilities
783 - 659 = 124
783 - 159 = 624
783 - 629 = 154
wait
1 + 2 + 3 +... + 300 this number sequence is equal to how many? Must have the formula and the solution
n=300 d=1
S=n(n+1)d=300*301*1/2=45150
If the sum of the first two terms of a sequence is equal to the second term, the general term formula can be obtained
Fibonacci sequence refers to such a sequence: 1,1,2,3,5,8,13,21 This sequence starts from the third term, and each term is equal to the sum of the first two terms. Its general term formula is: [(1 + 5) / 2] ^ n / √ 5 - [(1 + 5) / 2] ^ n / √ 5 [√ 5 represents radical 5]. This paper proves that its recurrence formula is a [n + 2