#CE1D 2019 Mathématiques - question 4 (aide à la préparation au CE1D Math/correction)

Solving a Math Problem

In this video, the speaker discusses how to solve a math problem that involves finding the common element between three cyclists who are riding around a pond at different speeds. The speaker provides a simple method for solving the problem and emphasizes the importance of not giving up on difficult problems.

Finding the Common Element

• The speaker suggests making a list of all the times each cyclist completes a lap around the pond.

• Using this method, we can find 15 elements for each cyclist.

• If we still haven't found a common time after listing 15 elements for each cyclist, we should continue listing more until we find one or realize we made an error in our calculations.

Importance of Perseverance

• The speaker emphasizes that even though solving this type of problem may be long and tedious, it's important not to give up because these types of problems often have high point values.

• To succeed in math, you don't need to be naturally gifted; you just need to be willing to work hard and persevere through difficult problems.

Methods for Finding a Common Multiple

In this section, the speaker discusses two methods for finding a common multiple. The first method involves calculating the time at which two people will meet again after starting at different times and moving at different speeds. The second method involves finding the smallest common multiple of three given numbers.

Method 1: Calculating Meeting Time

• Method involves finding the time at which two people will meet again after starting at different times and moving at different speeds.

• To find the meeting time, calculate the least common multiple (LCM) of their respective times.

• Example problem solved using this method.

Method 2: Finding Smallest Common Multiple

• Second method involves finding the smallest common multiple of three given numbers.

• To find the smallest common multiple, factor each number into its prime factors and then take all factors with their highest exponents.

• Example problem solved using this method.

Overall, both methods are effective in finding a common multiple but require different levels of mathematical knowledge.