PSLE The first 15 numbers of a number pattern are given.
0, 1, 7, 9, 0, 1, 7, 9, 0, 1, 7, 9, 0, 1, 7, ...
- What is the 331st number?
- What is the sum of the first 349 numbers?
(a)
Each set of numbers: 0, 1, 7, 9
Each set has 4 numbers.
Remainder: 1 → Number 0
Remainder: 2 → Number 1
Remainder: 3 → Number 7
Remainder: 0 → Number 9
331 ÷ 4 = 82 r 3
331st number = 7
(b)
Sum of each set
= 0 + 1 + 7 + 9
= 17
Number of sets
= 349 ÷ 4
= 87 r 1
First 1 number = 0
Sum of the first 349 numbers
= (87 x 17) + 0
= 1479 + 0
= 1479
Answer(s): (a) 7; (b) 1479