Units Decameter, Hectometer

### 1.1. Knowledge to remember

- The decimeter is a unit of length.

Decameter is abbreviated as **dam**.

**1dam = 10m**

- The hectometer is a unit of length.

Hectometer is abbreviated as **hm**.

**1hm = 100m**

**1hm = 10dam**

### 1.2. Solving Textbook Exercises

**Lesson 1:** Number ?

1hm = … m 1dam = … m 1hm =…dam 1km = … m |
1m = … dm 1m = … cm 1cm = …mm 1m = …mm |

**Solution guide**

Use the following knowledge: 1dam = 10m; 1hm = 100m; 1hm = 10dam and other knowledge about length units learned.

1hm = 100 m 1dam = 10 m 1hm = 10 dam 1km = 1000 m |
1m = 10 dm 1m = 100 cm 1cm = 10mm 1m = 1000mm |

**Lesson 2: **a) 4 dam = ….. m

**Comment:**

4 damage = 1 damage x 4

= 10 mx 4

= 40m.

b) Write the correct number in the dot (follow the pattern)

** Form: **4 damage = 40m 8hm = 800m

7 dam = … m 7hm = … m

9 dam = … m 9hm = … m

6 dam = … m 5hm = … m.

**Solution guide**

Use the method of sentence a and then fill in the blanks with appropriate numbers.

b) 7 dam = 70 m 7hm = 700m

9 damage = 90m 9hm = 900m

6 dam = 60m 5hm = 500m.

**Lesson 3:** Calculate (according to form)

** Form: **2dam + 3dam = 5dam

24dam – 10dam = 14dam

25dam + 50dam = 8hm + 12hm = 36hm + 18hm = |
45dam – 16dam = 67 hm – 25 hm = 72hm – 48hm = |

**Solution guide **

Add two numbers and then write the length unit after the result you just found.

25dam + 50dam = 75dam 8hm + 12hm = 20hm 36hm + 18hm = 54hm |
45dam – 16dam = 29dam 67 hm – 25 hm = 42 hm 72hm – 48hm = 24hm |

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