Question

Explain how you can be sure that all the rates you have written on a double number line are correct.

Answer 1

Answer:

By checking the ratio of the upper number and lower number.

Step-by-step explanation:

We know that, 'double number line' is a line having numbers on both the sides as we can see below.

Now, since we are plotting numbers on both the sides, it is required that they are correctly placed in order to form a valid 'double number line'.

So, to check the validity of the double number line, we check whether the ratio of the upper number and the lower number is same.

for e.g. As we can see from the figure below, the ratio of numbers is,

$\frac{1}{10}$ has 1 : 10, $\frac{2}{20}$ has 1 : 10 .... and $\frac{10}{100}$ has 1 : 10.

Since, the ratio of the numbers is same. We say that the double number line is correct.

Hence, by checking the ratio of the upper and lower number, we can say that the number line is correct or not.

Answer 2

You can check all the rates on the number line by finding the quotient between the top rate and the bottom rate given and make sure that all of your quotients are equal to the given rate.