This fast calculation trick or vedic maths trick will teach you how to multiply any number by 5. The concept can be divided in two parts as shown-
MULTIPLYING 5 TIMES AN EVEN NUMBER
Memory Trick: Halve the number you are multiplying by and place a zero after the number.
i. 5 × 136, half of 136 is 68, add a zero for an answer of 680.
ii. 5 × 874, half of 874 is 437; add a zero for an answer of 4370.
MULTIPLYING 5 TIMES AN ODD NUMBER: subtract one from the number you are multiplying, then halve that number and place a 5 after the resulting number.
343 x 5 = (343-1)/2 | 5 = 1715