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Which of the following numbers is divisible by 4?
9876754
8978624
7864534
9876342
8978624
Check only the last two digits of each number and divide by 4. If the two-digit number is divisible by 4, the entire number is divisible by 4.
Four options containing large numbers: A) 9876754, B) 8978624, C) 7864534, D) 9876342
A number is divisible by 4 if the number formed by its last two digits is divisible by 4.
Check only the last two digits of each number and divide by 4. If the two-digit number is divisible by 4, the entire number is divisible by 4.
Trying to divide the entire large 7-digit number by 4 instead of applying the divisibility rule for 4 (looking at the last two digits).
Step 1: Understand the Divisibility Rule for 4
A natural number is divisible by 4 if and only if the number formed by its last two digits (tens and units digits) is divisible by 4.
Last two digits(mod4)=0
Step 2: Check Option A (9876754)
The last two digits are 54. Dividing 54 by 4: 54÷4=13.5 (not an integer). Therefore, 9876754 is not divisible by 4.
54÷4=integer
Step 3: Check Option B (8978624)
The last two digits are 24. Dividing 24 by 4: 24÷4=6, which is an integer. Thus, 8978624 is divisible by 4.
24÷4=6
Step 4: Check Options C and D
For Option C (7864534), the last two digits are 34 (34÷4=8.5). For Option D (9876342), the last two digits are 42 (42÷4=10.5). Neither is divisible by 4.
34 and 42 are not multiples of 4
B is correct because the last two digits of 8978624 form the number 24, which is divisible by 4 (24 ÷ 4 = 6).
Similar divisibility rules exist for powers of 2: for 4 look at last 2 digits, for 8 look at last 3 digits, and for 16 look at last 4 digits.