Page 123 - NUMINO Challenge_B2
P. 123
14 Streetlights and Logs
Basic Concepts Simplifying to Solve
Drawing a diagram or finding rules to solve a complicated problem is called
simplifying a problem.
Complicated Make problem Draw a diagram
problem simpler and find rules
Solve the
simplified problem
Example Students are standing in a circle. Each student is holding a number
card, starting from 1. If the distance between each student is the
same, and the student holding number card 13 is directly across
from the student holding number card 30, how many students are
standing in the circle?
Class Notes
If four students are standing in a circle, the difference between the 1
numbers of the students directly opposite each other is 3 1 42
42 . 3
If six students are standing in a circle, the difference between the numbers 1
of the students directly opposite each other is 6 3 62
53
.
4
From and , the number of students is times the difference
between the numbers of the students directly opposite each other.
Therefore, if student 13 is directly across from student 30, the total number
of students is ( ).
Try It Again Alice planted flowers at a certain distance along the edge of a
circular garden. If the 8th flower and the 21st flower were directly
across from each other, how many flowers did she plant?
120 NUMINO Challenge B2
Basic Concepts Simplifying to Solve
Drawing a diagram or finding rules to solve a complicated problem is called
simplifying a problem.
Complicated Make problem Draw a diagram
problem simpler and find rules
Solve the
simplified problem
Example Students are standing in a circle. Each student is holding a number
card, starting from 1. If the distance between each student is the
same, and the student holding number card 13 is directly across
from the student holding number card 30, how many students are
standing in the circle?
Class Notes
If four students are standing in a circle, the difference between the 1
numbers of the students directly opposite each other is 3 1 42
42 . 3
If six students are standing in a circle, the difference between the numbers 1
of the students directly opposite each other is 6 3 62
53
.
4
From and , the number of students is times the difference
between the numbers of the students directly opposite each other.
Therefore, if student 13 is directly across from student 30, the total number
of students is ( ).
Try It Again Alice planted flowers at a certain distance along the edge of a
circular garden. If the 8th flower and the 21st flower were directly
across from each other, how many flowers did she plant?
120 NUMINO Challenge B2
