الرياضيات (بالإنجليزية) الصف الرابع الابتدائي، الأسبوع 8: Times as many: comparing by multiplying

Multiplicative comparison

الأسبوع 8 · المقارنة بالضرب · 3 دروس

Times as many: comparing by multiplying

Discover Mathematics P4: Term 1, Unit 5, Lessons 1–3

GoalCompare two amounts by saying how many times as many one is as the other.

New words

times as many · a comparison by multiplying: 3 times as many as 4 is 3 × 4more than · a comparison by adding: 3 more than 4 is 4 + 3multiplicative comparison · comparing two amounts by how many times bigger one is

Explanation

There are two ways to compare numbers. We can say how many more: Mina has 4 stickers and Hana has 3 more, so Hana has 4 + 3 = 7. Or we can say how many times as many: Hana has 3 times as many as Mina, so she has 3 groups of 4, which is 3 × 4 = 12 stickers. These two ways give different numbers. When we hear times as many, we multiply. In a bar model the smaller amount is one bar and the bigger amount is several bars of the same size. Count the bars to see how many times as many. Twice as many means 2 times as many, and we also say double.

Worked examples

Mina has 4 stickers. Hana has 3 times as many. The bar model shows 3 bars of 4. Hana has 4 + 4 + 4 = 12 stickers, which is 3 × 4.

A tuk-tuk carries 3 passengers. A microbus carries 5 times as many. The microbus carries 5 × 3 = 15 passengers. If the microbus carried 5 more, it would carry 3 + 5 = 8. Times as many and more than are different.

Ribbon	Times as long	Length (cm)
red	1	6
blue	2	12
green	4	24

A red ribbon is 6 cm. A blue ribbon is twice as long. The blue ribbon is 2 × 6 = 12 cm. A green ribbon is 4 times as long as the red one: 4 × 6 = 24 cm.

Class activity

Groups game. Take 3 beans for yourself. Your partner takes 4 times as many. Count the partner beans. Then your partner takes 4 more than you. Compare the two piles. Repeat with other numbers and say each time: times as many or more than?

Practice

Karim has 5 marbles. Seif has 6 times as many. How many marbles does Seif have?

A pencil costs 3 LE. A notebook costs 4 times as much. How much is the notebook?

Farida has 8 stamps. Jana has 8 more. Marwan has 8 times as many. Who has more, Jana or Marwan, and how many do they have?

A palm tree is 9 m tall and a young tree is 3 m tall. How many times as tall is the palm tree?

Aya says 20 is 5 more than 4 and also 5 times as many as 4. Is she right?