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2 years ago

Give one example of when you would use the friendly numbers strategy to subtract.

2 answers:

5 0

I would say: when we want to substract numbers that are close to each other, but when the respective digits of the number from which the second number is subtracted are lower than in the other number.

For example, when we want to substract 18 from 21. Those two numbers are very close, but if you did it digit by digit, your would run into a problem.

So instead you can collect their differences to the friendly number 20: 21 is one number away from 20, and 18 two numbers, which makes a total of 3 numbers: and 3 is the solution!

Igoryamba2 years ago

3 0

For this case, we use the strategy of friendly numbers when subtraction is something complex to do mentally.

Let's suppose that we have the following subtraction:

$117 - 83$

Using friendly numbers we have:

$(100 + 17) - (80 + 3)$

Then, applying the associative property we have:

$(100 - 80) + (17 - 3)$

Doing the calculations we have:

$20 + 14 = 34$

Finally we have:

$117 - 83 = 34$

You might be interested in

Do oddsmakers believe that teams who play at home will have home field advantage? Specifically, do oddsmakers give higher point

vladimir2022 [97]

Answer:

Option 3 is correct.

The data do not provide sufficient evidence to reject H0; thus, we cannot conclude that the mean point spread of home games is higher than that of away games.

Step-by-step explanation:

Before anything else, we first give the null and alternative hypothesis for this question.

Null hypothesis would be that there isn't significant evidence to conclude that the mean point spread of home games is higher than that of away games.

H0: µ1 = µ2

And the alternative hypothesis would be that there is significant evidence to conclude that the mean point spread of home games is higher than that of away games.

Ha: μ1 > μ2

The data from the output of the analysis of the hypothesis test is missing from the question. It was obtained online and is attached to this solution of the question.

The table consists of the difference, the sample mean, the standard error of the mean, degree of freedom, the test statistic and most importantly, the p-value. It is the p-value that absolutely gives us the concluding statement of the hypothesis testing.

When the significance level for a test isn't provided, the convention is usually to use 5% significance.

Interpretation of p-value

When the (p-value > significance level), we fail to reject the null hypothesis and when the (p-value < significance level), we reject the null hypothesis and accept the alternative hypothesis.

So, for this question, significance level = 0.05

p-value = 0.4351

0.4351 > 0.05

Hence,

p-value > significance level

This means that we fail to reject the null hypothesis & say that 'The data do not provide sufficient evidence to reject H0; thus, we cannot conclude that the mean point spread of home games is higher than that of away games'.

Hope this Helps!!!

7 0

2 years ago

Marine ecologists estimate the reproduction curve for swordfish in a fishing ground to be f(p) = −0.01p2 + 9p, where p and f(p)

Nimfa-mama [501]

Answer:

The population that gives the maximum sustainable yield is 45000 swordfishes.

The maximum sustainable yield is 202500 swordfishes.

Step-by-step explanation:

Let be $f(p) = -0.01\cdot p^{2}+9\cdot p$ , the maximum sustainable yield can be found by using first and second derivatives of the given function: (First and Second Derivative Tests)

First Derivative Test

$f'(p) = -0.02\cdot p +9$

Let equalize the resulting expression to zero and solve afterwards:

$-0.02\cdot p + 9 = 0$

$p = 450$

Second Derivative Test

$f''(p) = -0.02$

This means that result on previous part leads to an absolute maximum.

The population that gives the maximum sustainable yield is 45000 swordfishes.

The maximum sustainable yield is:

$f(450) = -0.01\cdot (450)^{2}+9\cdot (450)$

$f(450) =2025$

The maximum sustainable yield is 202500 swordfishes.

6 0

2 years ago

Solve for x: the quantity x plus fifty all over two equals thirteen times x

dusya [7]

Answer:

x = 2

Step-by-step explanation:

(x + 50)/2 = 13x, first multiply both sides by 2

x + 50 = 26x, next subtract x from both sides

50 = 25x, finally divide both sides by 25

2 = x

3 0

2 years ago

Read 2 more answers

The volume of a right triangular prism is 72 cubic feet. The height of the prism is 9 feet. The triangular base is an isosceles

Alexxx [7]

What is the area of the triangular base?
8 square feet

What is the length of edge DF?
4 feet

3 0

2 years ago

Read 2 more answers

In professional basketball games during 2009-2010, when Kobe Bryant of the Los Angeles Lakers shot a pair of free throws, 8 time

ziro4ka [17]

Answer:

Is plausible that the successive throws are independent

Step-by-step explanation:

1) Table with info given

The observed values are given by the following table

__________________________________________________

First shot Made Second shot missed Total

__________________________________________________

Made 152 33 185

Missed 37 8 45

__________________________________________________

Total 189 41 230

2) Calculations and test

We are interested on check independence and for this we need to conduct a chi square test, the next step would be find the expected value:

Null hypothesis: Independence between two successive free throws

Alternative hypothesis: No Independence between two successive free throws

_____________________________________________________

First shot Made Second shot missed

_____________________________________________________

Made 189(185)/230=152.0217 41(185)/230=32.9783

Missed 189(45)/230=36.9783 41(45)/230=8.0217

_____________________________________________________

On this case all the expected values are higher than 5 and the sample size 230 is enough to apply the chi squared test.

3) Calculate the chi square statistic

The statistic for this case is given by:

$\chi_{cal}^2 =\sum \frac{(O_i -E_i)}{E_i}$

Where O represent the observed values and E the expected values. Replacing the values that we got we have this

$\chi_{cal}^2 =\frac{(152-152.0217)^2}{152.0217}+\frac{(33-32.9783)^2}{32.9783}+\frac{(37-36.9783)^2}{36.9783}+\frac{(8-8.0217)^2}{8.0217}=0.000003098+0.00001428+0.00001273+0.0.00005870=0.00008881$

Now with the calculated value we can find the degrees of freedom

$df=(r-1)(c-1)=(2-1)(2-1)=1$ on this case r means the number of rows and c the number of columns.

Now we can calculate the p value

$p_v =P(\chi^2 >0.00008881)=0.9925$

On this case the pvalue is a very large value and that indicates that we can fail to reject the null hypothesis of independence. So is plausible that the successive throws are independent.

5 0

2 years ago