Reviewing charts

**Lesson 1: **Based on the chart below, answer the following questions

THE NUMBER OF PICTURES OF THE FOUR CUTTING nests

a) How many shapes can all four groups cut? How many triangles, squares and rectangles are there?

b) How many squares more squares can Group 3 cut than Group 2, but how many rectangles less than Group 2?

**Solution guide:**

- Observe the graph to find the number of shapes that each nest can cut, then find the square difference of group 3 and group 2, and the difference of rectangles of group 2 and group 3.

a) All four nests cut 16 shapes, of which there are 4 triangles, 7 squares and 5 rectangles.

b) Group 2 can cut 1 triangle, 1 square, 2 rectangles.

Group 3 can cut 1 triangle, 2 squares, 1 rectangle.

So nest 3 can cut more than nest 2 is 1 square, but less than nest 2 is 1 rectangle.

**Lesson 2: **The chart below shows the area of three cities in our country (according to 2002 data).

Based on the chart, answer the following questions:

a) How many square kilometers is the area of Hanoi, how many square kilometers is the area of Da Nang, and how many square kilometers is the area of Ho Chi Minh City?

b) How many square kilometers is the area of Da Nang larger than the area of Hanoi and how many square kilometers smaller than the area of Ho Chi Minh City?

__Solution guide:__

- Observe the graph to find the area of each city, then find the area difference between Da Nang city and Hanoi city, and the area difference between Ho Chi Minh city and Da Nang city.

a) The area of Hanoi is: 921km^{2}.

The area of Da Nang is: 1255km^{2}.

The area of Ho Chi Minh City is : 2095km^{2}.

b) The area of Da Nang is larger than the area of Hanoi:

1255 – 921 = 334 (km^{2})

The area of Da Nang is smaller than the area of Ho Chi Minh City.

2095 – 1255 = 840 (km^{2})

**Lesson 3: **The chart below shows how much fabric a store sold in December

Show that each roll of fabric is 50m long. Based on the chart, answer the questions below:

a) How many meters of fabric did the shop sell in December?

b) In December, how many meters of fabric did the shop sell in all?

__Solution guide:__

- Look at the chart to find the number of rolls of each fabric the store has sold.
- Find the number of meters of floral fabric = length of 1 roll of fabric × × number of rolls of floral fabric.
- Find the total number of meters of fabric sold = length of 1 roll × × number of rolls of fabric sold.

Looking at the chart, we can see that in December, the store sold 42 rolls of floral fabric, 50 rolls of white fabric and 37 rolls of blue fabric.

*Solution*

a) The number of meters of fabric sold by the shop in December is:

50 x 42 = 2100 (m)

b) The total number of rolls of fabric the shop sold in December was:

42 + 50 + 37 = 129 (roll)

The number of meters of fabric the store sold in all in December was:

50 x 129 = 6450 (m)

Answer: a) 2100m.

b) 6450m.

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