41
Number ray and scales
Textbook: Part 2, lesson 41, pp. 7–9
GoalRead a number ray and a scale: find the value of one division.
New words
scale · shkalavalue of one division · bo‘linma qiymatimark · belgiequal part · teng qism
Explanation
On a number ray or a scale, the gap between two neighbouring marks is one division. To find its value we divide the difference of two marks by the number of equal parts. If there are 4 equal parts between 0 and 100, one division is 100 : 4 = 25. Knowing it, we can find the number at any mark.
Worked examples
Between 0 and 60 there are 6 parts: a division is 60 : 6 = 10. The 4th mark is 10 × 4 = 40.
Between 200 and 500 there are 6 parts: a division is (500 − 200) : 6 = 50. The 1st mark after 200 is 250.
Class activity
“Scale workshop”: draw a ray from 0 to 100 in your notebook and split it into 5, 10 and 4 equal parts; each time write the value of a division.
Practice
1
On a number ray there are 4 equal parts between 0 and 100. What is the value of one division?
25
2
There are 6 equal parts between the marks 200 and 500. Find the value of one division.
50
3
A scale goes from 0 to 1 000 and is split into 5 equal parts. Which number is at the 3rd mark?
600
4
A kitchen scale goes from 0 to 500 g with 10 equal divisions. The pointer is at the 7th mark. How many g is the food?
350