Presentation on theme: "L.O.1 To recall multiplication facts up to 10 x 10"— Presentation transcript:
1L.O.1 To recall multiplication facts up to 10 x 10
2Don’t draw the table just write the missing answers in order in your book. X5739428625401828242 ½ minutes
3Which multiplication facts are hard to remember? Why do you think that is?Which are easy to remember?
4To understand area measured in square centimetres L.O.2To understand area measured in square centimetresTo begin to understand the formula“length x breadth” for the area of a rectangle
5What do we mean by the word “area”? Show where the area of your table top is.REMEMBER…The area of a 2-D shape is the amount of surface within its perimeter.
6Q. How can we work out the area of this rectangle?
7We can do it by counting the squares. The rectangle has 24 squaresIts area can be written as24 square centimetres or 24 cm².
8Draw 2 rectangles in your book. Write the dimensions and areas next to each.Be prepared to explain your working.Q. Is there a quick way to find the area of a rectangle?
9You should find that multiplying the number of squares in each row by the number in each column gives the area.These numbers are equivalent to the length and the width / breadth.So the area of a rectangle can be written as length x breadth or length x width.
10Check this theory by drawing more rectangles: Prisms draw 6SpheresTetrahedra 4but consider….Q. If you double the length of a rectangle what happens to its area?Q. What would happen to the area if you doubled the length and the width?
11This is a patio.Each paving slab measures 60cm by 60 cm.Q. If we had used 30cm by 30 cm. paving slabs would we have used twice as many?
12We would have used 4 times as many because we need 4 small slabs to cover each large one.
23If we halve these numbers how can we express the answers?Will they be fractions or decimals?
2424Q. What is a quick way to multiply this number by 4?
25Doubling twice is the quick mental method to multiply by four. We’ll multiply each of these aloud by 4.
26L.O.2To be able to understand area measured in square centimetres.To understand and use the formula in words “length x breadth” forthe area of a rectangle.
27Here we have a square metre. cm²We used cm² to find the areas of shapes in yesterday’s lesson.Here we have a square metre.1metreHow many cm² are there in I square metre?How can we work it out?1m²1metre
281m² = 10 000cm² because length = 100cm. and breadth = 100cm. and cm x 100cm = cm²
291mm²Try to imagine a millimetre squareQ. How many mm² are there in 1cm²?Q. How can we work it out?
301cm² = 100mm² because length = 10mm and breadth = 10mm and 10cm x 10 cm = 100mm²
31Which of the three units ( m² ,cm² , or mm²) would be best for measuring these? 1. The classroom floor.2. An exercise book.3. A postage stamp.The playground.A chocolate bar wrapper.6. A mouse mat.7. Your thumbnail.
32. Q. What is the approximate area of the rectangle? 2.8 cm 6.1 cm The area of a rectangle is length x breadth or l x b for short.Here the area would be x but it is useful first to get anESTIMATEQ. What is the approximate area of the rectangle?
33. 2.8 cm 6.1 cm Rounding UP and DOWN leads to an approximate area of 6 x 3 = 18cm²
341. 2. Let’s try with these: 1.7cm 5.9 cm Rounding UP and DOWN leads to 6cm x 2 cm = 12cm²2.3.2cm11.8cmRounding UP and DOWN leads to 12cm x 3 cm = 36cm²
36. In which rectangles do you think the area has been underestimated? Using calculators we’ll check your estimates but will round part-answers to the nearest whole number.Q. What areas of shapes in the classroom would you measure in mm², cm², or m²?Record about a dozen altogether.
37Extension: measure area to two decimal points. In your book draw rectangles using cm and mm and write their length and breadth. Be accurate!Your partner must first estimate the area by rounding up or down then work out the area to the nearest whole number using a calculator.Record both the estimate and the final answer.Tetrahedra draw 2Spheres draw 3Prisms drawExtension: measure area to two decimal points.
38By the end of the lesson children should be able to: Express the formula for the area of a rectangle first in words then in letters.Choose a suitable unit to estimate the area.