Lesson Video: Subtracting Tens | Nagwa Lesson Video: Subtracting Tens | Nagwa

# Lesson Video: Subtracting Tens Mathematics • 1st Grade

In this video, we will learn how to subtract a multiple of ten from a multiple of ten and model this with place value equipment.

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### Video Transcript

Subtracting 10s

In this video, we will learn how to subtract a multiple of 10 from a multiple of 10 and model this with place-value equipment.

A multiple of 10 is a number which can be divided by 10 without a remainder. 10 is a multiple of 10. 20 is a multiple of 10, so are the numbers 30, 40, 50, 60, 70, 80, 90, and 100. We can model multiples of 10 using place-value equipment such as 10s blocks. This model shows the number 50 using five 10s, and it has no ones. Five 10s are 50. Let’s take away 10. If we take away one 10, instead of having five 10s, we have four 10s. Four 10s are 40. Five 10s take away one 10 equals four 10s. 50 take away 10 equals 40.

We subtracted a multiple of 10, 10, from 50, which is also a multiple of 10. And we used place-value equipment to help. Let’s try some questions to help us practice subtracting a multiple of 10 from a multiple of 10. And we’ll use place-value equipment to help.

Matthew is subtracting 10s. Eight 10s take away three 10s. Find the missing numbers. Eight 10s take away three 10s is what 10s. 80 subtract 30 equals what.

In this question, we’re subtracting a multiple of 10 from a multiple of 10. We know that Matthew has eight 10s, and he subtracts three 10s. How many 10s does he have left? One, two, three, four, five. Eight 10s take away three 10s is five 10s. What are five 10s worth? If our number has five 10s and no ones, the number is 50. Let’s count in 10s to check. 10, 20, 30, 40, 50. 80 subtract 30 equals 50. Eight 10s take away three 10s equals five 10s. 80 take away 30 equals 50.

Subtract to find the difference. Hint: think about 10s and ones. Use base 10 blocks to help you. Six subtract four equals what. 60 subtract 40 equals what.

In this question, we’re told to think about 10s and ones and use base 10 blocks to help us subtract four from six and 40 from 60. If we have six base 10 blocks and then we subtract four 10s, how many 10s do we have left? There are two. We know that six subtract four is two. Six 10s subtract four 10s equals two 10s. 60 subtract 40 equals 20. Six 10s are 60. If we subtract four 10s or 40, we have two 10s left. And two 10s are 20.

Complete the following. 70 subtract 50 equals what.

We can model the number 70 using 10s blocks. How many 10s do we need to make the number 70? There are seven 10s and no ones. 10, 20, 30, 40, 50, 60, 70. We have to subtract 50. If we subtract 10, we’re left with 60. We subtracted two 10s, which is 20. Now, we’ve subtracted 30, 40, 50. We had seven 10s. We subtracted five 10s. And we’re left with two 10s. Two 10s are 20. So, 70 subtract 50 equals 20.

Complete the following: 60 subtract what equals 10.

In this question, we have to find the missing number. In other words, what do we need to subtract from 60 to leave us with 10? We can use six 10s to model the number 60. 10, 20, 30, 40, 50, 60. Let’s take away 10s until we’re left with 10. We have 60. If we take away one 10, we’re left with 50. If we take away two 10s, we have 40 left. If we take away three 10s, we’re left with 30. If we take away four 10s, we have 20 left. And if we take away five 10s, we have 10 left.

How much did we take away altogether? Five 10s are 10, 20, 30, 40, 50. If we have six 10s or 60 and we take away 50, we’re left with 10. The missing number is 50.

What have we learned in this video? We’ve learned how to use place-value equipment to subtract a multiple of 10 from a multiple of 10.