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Adding and subtracting on number line word problems

Sal uses number lines to solve addition and subtraction word problems with numbers less than 100.

Want to join the conversation?

• Is using a number line the best way to add and subtract? Because in some cases, it seems easier to not use a number line.
• Whatever is better for you. A number line is just a good illustration of what actually happens when adding or subtracting. As you go up, you won't need them at all (adding with them).
• if abcs work with numbers what is the number song?
• there isn't one, there is no stop to numbers, there are an infinite amount of numbers.
• . Why do I have to use a number line if I can quickly solve 30 + 4 + 3 + 2 to get 39?
• Using a number line makes addition easier for those who are weaker in that area
• How can I become a math genius who can do for example 583^2 in their head or something? They are born that way?
• Good question!

I often square numbers by using the property (a+b)^2 = a^2+2ab+b^2 (which follows from using the distributive property twice, or using an area model).

l would think of 583^2 as [600+(-17)]^2, which becomes
600^2+2*600*(-17)+(-17)^2
= 360,000-20,400+289
= 339,889.

• hi what is 63 + 27 on a number line
• We can use the addition trick of taking away 3 from the 63 and giving the 3 to the 27. This gives the easier addition problem 60 + 30. The answer is 90.
• what is 12,000000+12,000000
• why can math be hard
when was math created
• Math is hard because it asks lots from our brains. Our human brains find other things easier, but things like painting or playing a violin are also hard. But if you practice they get easier.

Khan academy is the creation of Mr Khan :)

Some parts of math are already coded in your brain. Like knowing what is bigger or what is more. Putting math into "words" happened a long time ago. More than a 1,000 years!
• Does it work the same way for negative numbers?
• how did you get 93? can you do an array and do number line? ^w^?
• how is the numberline useful cause this is hard i get them wrong and get 40 30 20 14 0 for my grade :(