<span>1. 5564÷91
I know that 9 * 6 = 56
5564 rounds to 5600
91 rounds to 9
Since 56/9 = 6, then 5600/90 is the same as 560/9 = 60
The estimate is 60
2. </span><span>5391÷25
5391 sounds to 5400
25 is 1/4 of 100.
That means when you divide by 25, you can divide by 100 and multiply by 4.
5400/100 = 54
54 * 4 = 216
Estimate: 216
3. </span><span>explain how to estimate 498÷12
48/12 = 4
498 is little more than 480, so 498/12 is little more than 40
4. </span><span>which is the closest estimate for 2130÷ 33
A.7 B.17 C.70 D.700
2130/33
Round off the numerator and denominator to
2100/30
Reduce the fraction
210/3
Since I know that 21/3 = 7, then 210/3 = 70
Estimate: 70
</span>
(a)
Q1, the first quartile, 25th percentile, is greater than or equal to 1/4 of the points. It's in the first bar so we can estimate Q1=5. In reality the bar includes values from 0 to 9 or 10 (not clear which) and has around 37% of the points so we might estimate Q1 a bit higher as it's 2/3 of the points, say Q1=7.
The median is bigger than half the points. First bar is 37%, next is 22%, so its about halfway in the second bar, median=15
Third bar is 11%, so 70% so far. Four bar is 5%, so we're at the right end of the fourth bar for Q3, the third quartile, 75th percentile, say Q3=40
b
When the data is heavily skewed left like it is here, the median tends to be lower than the mean. The 5% of the data from 80 to 120 averages around 100 so adds 5 to the mean, and 8% of the data from the 60 to 80 adds another 5.6, 15% of the data from 40 to 60 adds about 7.5, plus the rest, so the mean is gonna be way bigger than the median of around 15.
find prime factors to get the inbetween numbers for product, and choose the one that has a difference of 20, and it should be 5 and 25, both requirements are met.
3x+15=0
<=> 3x=-15
<=> x= -15/3
<=> x= -5
Vậy nghiệm của đa thức 3x+15 là -5
