英數(暑期作業)

3.For integers that lie between 1 to 10 (excluding 10 itself),subtract the sum of all the prime numbers from the sum of all the composite numbers,find the difference.

prime numbers for integers that lie between 1 to 10 (excluding 10 itself) are
2, 3, 5, 7

thus, the sum of all the prime numbers
= 2 + 3 + 5 + 7
= 17

composite numbers for integers that lie between 1 to 10 (excluding 10 itself) are
4, 6, 8, 9

Thus, the sum of all the composite numbers
= 4 + 6 + 8 + 9
= 27

therefore, the difference of the sum of all composite numbers minus the sum of all prime numbers
= 27 - 17
= 10 (Ans.)

Ans. The difference is 10.

4.The fourth multiple of is divided by the second multiple of 6.Find the quotient.

The fourth multiple of 6 = 6 * 4 = 24

The second multiple of 6 = 6 * 2 = 12

Thus, the quotient = 24 / 12 = 2 (Ans.)

5.Jacky ate 35% of a watermelon.find the percentage of watermelon remaining.

The percentage of watermelon remaining = 1 - 35% = 100% - 35% = 65% (Ans.)

6.The area of a school hall has increased by 23 % after re-construction.what percentage of the previous area is the new area?

The area of the new area = 1 * (1 + 23%) = 123%

Thus, the percentage of the previous area is the new area
= 1 / (123%)
= 81.3% (apprp.) (Ans.)