-1,-2,-3
10-1=9
9-2=7
7-3=4
10
26 As far as I can tell the sequence is +10,-5,+10,-5.
The sequence consists of triangular numbers, which can be calculated using the formula ( T_n = \frac{n(n + 1)}{2} ). The numbers in the sequence correspond to ( T_1, T_3, T_5, T_6, T_7, T_8, T_9 ) respectively. Following this pattern, the next number is ( T_{10} = \frac{10(10 + 1)}{2} = 55 ). Therefore, the next number in the sequence is 72.
it is 7
If you mean: 5, 10, 20, 40 then the following number is twice the previous number which will be 80
10
5
10
10
26 As far as I can tell the sequence is +10,-5,+10,-5.
The sequence consists of triangular numbers, which can be calculated using the formula ( T_n = \frac{n(n + 1)}{2} ). The numbers in the sequence correspond to ( T_1, T_3, T_5, T_6, T_7, T_8, T_9 ) respectively. Following this pattern, the next number is ( T_{10} = \frac{10(10 + 1)}{2} = 55 ). Therefore, the next number in the sequence is 72.
Dodging numbers may be missing numbers in a sequence. For example, the underscore in the following sequence represents such a number: 2, 4, _ , 8, 10.
it is 7
15
If you mean: 5, 10, 20, 40 then the following number is twice the previous number which will be 80
16
5+5 = 10 10+5 = 15 15-5 = 15 10+5 = 15