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## Early math review

### Course: Early math review > Unit 5

Lesson 10: Word problems with "more" and "fewer" (within 100)- Addition word problem: starfish
- Addition word problem: spots
- Multi step addition word problem
- 2-step addition word problems within 100
- Subtraction word problem: basketball
- Multi-step subtraction word problem
- 2-step subtraction word problems within 100

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# Addition word problem: starfish

Sal solves a word problem with the term "fewer".

## Want to join the conversation?

- Why so many lessons of the same thing?(4 votes)
- There's multiple lessons because each video is a different example to help with understanding.(3 votes)

- fraction multiplication?(5 votes)
- 0+0, 0+1, 0+2 etc. There's 100 different combinations for all the single digit addition problems I think because there are 10 unique numbers plus each number. 10 x 10 = 100, but how many double and single digit combinations are there? 0+0, 1 + 1.. etc to 87 + 95.... to 99 + 99 etc.(5 votes)
- (10x10)x(10x10)=10000

one ten for each place value, since 2 digit number has 2 place value there are 100 possible double digit numbers from 00 to 99.(1 vote)

- ithought we had to subtract(3 votes)
- what does he mean in3:00?(2 votes)
- @Is Sal

Hi there! Let's walk through the steps together to see if this helps:

1

59

28*_____*

87

Steps are below:

1) We want to add**59**and**28**

2) Begin by adding**9**and**8**which are located in the*ones*place. Because**9**+**8**=**17**we need to carry the**7**down to the*ones*place and**1**to the*tens*place above the other*tens*known in this problem as**5**and**2**

3) Now we can add all the numbers in the*tens*place. Those numbers are**1**,**5**, and**2**. The total should be**8**

4) Then we can bring**8**down to the*tens*place in front of its friend**7**

5) Last, you have your answer :)! Our answer is**87**.**8**is in the*tens*place and**7**is in the*ones*place.

Please let me know if you need help with a different topic discussed in this video. Good question**Is Sal**

You can learn anything,

Fellow Khan Academy student <3(3 votes)

- Why do they call it 2 step word problem?(2 votes)
- because it has 2 steps?! ??!?!?!?!?!?(1 vote)

## Video transcript

- [Voiceover] Jacques took a submarine to the bottom of the ocean and discovered an underwater city. The starfish ruled the city. This is fascinating. There were 59 seahorses there, which was 28 fewer than the number of starfish. 28 fewer than the number-- I already used that color. Than the number of starfish. How many starfish, how
many starfish were there? So let's think about this
second sentence, here. So, number of seahorses is 28 fewer than the number of starfish. So we could write, we could write, number of seahorses, seahorses, is 28 fewer than
the number of starfish. So that means that this is going to be equal to then number of starfish. Number of starfish, starfish minus 28. 28 fewer than the number of starfish. So, let me write that in blue. So, if I have the number of starfish, and I go 28 fewer than that, that's going to be the
number of seahorses. That's what they tell us. The number of seahorses. "There were 59 seahorses there, "which was 28 fewer than
the number of starfish." And, they actually tell us what the number of seahorses is. It's 59, so we could write this as-- We could write this as, 59 is equal to the number of starfish. Number, actually maybe I'll just draw-- well I'll write it out, starfish. The number of starfish minus 28. Minus 28. Or, another way to think about it is there's 28 more starfish than seahorses. So we could rewrite this as saying, well whatever the number of seahorses are, whatever the number of seahorses are, they tell us, there's 59 seahorses. There's going to be 28 more. There's going to be 28 more starfish. Whenever you do a problem like this, it's always a good idea
just to do a check. Just to say, "Okay, are
there going to be more "starfish or more seahorses?" And when you look at the
information they give us, they say they there are 59 seahorses which was 28 fewer than
the number of starfish. So, if there are fewer
seahorses than starfish, that tells you there's
going to be more starfish. So it makes sense. If you want to go from the seahorses, the number of seahorses
to the number of starfish, you would add 28 because there is more starfish than seahorses. So now we just have to figure out what 59 plus 28 is, so let's do that. So, 59 is five 10s, and nine, ones. 28, let's write the two
10s in the 10s place, and the eight ones, in the one's place. We're adding. We're going to go from the number of seahorses add 28 more than that to get to the number of starfish. So let's first go to the one's place. Nine ones, plus eight ones is 17 ones. Write the seven ones, and one 10, or you could think of
it as I carried the one. But all I did was I
wrote the one 10 in 17, I wrote that in the ten's place. And now I could add one 10, plus five 10, plus two 10s. So let's see. One, plus five, plus two is eight. Eight tens. So the number of starfish is 87. And you should always
see if that makes sense. The number of starfish is, this right over here, is 87. So, if there are 59 seahorses, is that 28 fewer than 87? Sure, it is. It's exactly 28 fewer. Like, that's what we used
to solve this question.