Question Video: Finding the Missing Addend in Function Machines Adding Multiples of Ten to Two Digit Numbers | Nagwa Question Video: Finding the Missing Addend in Function Machines Adding Multiples of Ten to Two Digit Numbers | Nagwa

# Question Video: Finding the Missing Addend in Function Machines Adding Multiples of Ten to Two Digit Numbers Mathematics • First Year of Primary School

All the robots have been working hard to make new numbers. Which multiple of 10 have they added?

03:12

### Video Transcript

All the robots have been working hard to make new numbers. Which multiple of 10 have they added?

In the picture, we can see three robots, and they seem to have been programmed to do a job involving numbers. We’re told that they’ve been working hard to make new numbers. Can you see what’s happening in the picture? Each robot is taking in a number. It’s then doing something to that number. But then finally, a new number comes out of the robot. Now, in the next sentence, we’re given a clue as to what’s happening here. We’re asked, which multiple of 10 have they added? We can tell a few things from this sentence. Firstly, we can tell that all the robots are doing the same thing. The question doesn’t ask us which multiples of 10. It’s just one multiple. They’re all doing the same thing.

The next thing we can tell is that they’re adding a number to the number that goes into them, and also we know what sort of number they’re adding. Each robot is adding the same multiple of 10. Now we know that a multiple of 10 is a number in the 10 times table. It’s what we get when we multiply another number by 10. So the robots could be adding 10, 20, 30, 40, and so on. But which multiple of 10 have they added? To find out the answer, we need to look at how the numbers change from the numbers that go in to the numbers that come out. And we could do this using place value grids.

With the first robot, the number that goes in is 22. So that’s two 10s, two ones. And the number that comes out is 62. So that’s six 10s, two ones. This is interesting, isn’t it? We started off with two ones, and we’ve ended with two ones. No ones have been added at all, but the number of tens that we have has gone from two to six. Can you see how many tens have been added by this robot? Two plus four more 10s makes six 10s, don’t they? And as we say, the robot hasn’t added any ones at all. And if we’ve got the right answer here, we’d hope that the other two robots have done exactly the same thing.

Our second robot has taken the number 14, which is one 10, four ones. And we can see that the new number it’s made is 54, five 10s, four ones. Once again, the number of ones hasn’t changed, but we’ve got four more 10s. The multiple of 10 that these robots are adding is 40, isn’t it? And if we just check the last robot, if we have six 10s or 60 and we add four 10s or 40, we’re going to end up with 10 10s, which is the same as 100. By adding a multiple of 10 each time, we notice that the number of ones doesn’t change. The number of tens, however, does. And these robots have increased the number of tens by four. And that’s how we know the multiple of 10 that each robot has added is 40.

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