Number line

Number line

The diagram  above illustrate the structure of number in number line, which sometimes use to show how number get bigger in one direction and smaller in the other direction.

Adding and Subtracting with number line, may seen confusing but keep the two rule below.

• The number goes up as you go right (+)
• The number goes down as you go left (-)

Example 1: 3 + 4 means, you start at 3 and jumps up 4 spaces to 7 (3+ 4 =7) as show in the  diagram below.

Example 2 : 9-2 means, start at 9 and jump down 2 spaces (9 -2=7) as show in the diagram below.

You can even be more advance with number line, if you try to solve some equation like this 3 +1 -2 + 4 - 3 - 2 (start at 3, up 1, down 2, up 4, down 3, down 2).

Do these:

•  2 - 7 + 2 + 4  
• 1 + 4 - 4 + 3
• 2 + 5 + 5 + 6 -5  and comment your answer...

Negative number line

You may have meet someone telling you, you can`t take away more than you have, but the true is you can indeed take away more than you have, which result in negative number (7-10 = -3).

Adding and subtracting negative number on number line is somehow mismatch, but if you stay calm it`s easy to understand. Say you have 2 Naira and you owe your best friend 5 Naira, if you pay him with the 2 Naira, now you are still owing him 3 Naira(which is -3 subtracting 3 Naira from your money which you don`t have that time) as show below.

start at 2 and go down 5 times as illustrate above.

Multiplying Negative and Positive number with number line. suppose you want to multiply any number by 2, circle every other number starting from 0 as show below (multiply of 2).

Now let calculate 2 × 2 which is equal to 4.

You start moving from 0 through it right and keep resting on the circled number till you do it two (2) times.

 (multiplying by 3, 4 ,5)try these and comment your answer ().

Negative number (-2 * 2)

circle from 0 to the left as show above and count the circled number till you count 2 times

also -2 * -2 =? (negative number against negative number).

Note: if you want to multiply something like (-2 * -2 or other number provided that they both have a negative sign in front), start at 0 and circle the number through the right, count from 0 two  (2)times to the right (for equation -2 × -2).

Note: Take a sheet of paper and do some of this type of equation then comment, to know if it`s understandable.

Dividing with number line, to divide a number against another on a number line, you write the bigger number (like 0, 1, 2 ...) starting at 0 on the number line.

Suppose you are to calculate 4 / 2 after you have follow the step above (diagram),  just split it in 2 (because it is dividing against 2)

Do these 

• 5 ÷ 10 
• 6 ÷ 3

☺Funny: Tape rule ruler are of number line... 

Tape rule

Don`t forget top comment if there is any question.