Page 24 - steps 3b.pdf

25
• Area of rectangles • • 1cm squared Balancing weights C
paper (RM 144)
~;;~)~t~ This rectangle is D ' These are standard weights up to SOOg. BOOK3b
PAGE 3q
5 cm long and 3 cm wide.
i ' W .. ~ Area = 15 square centimetres. r' I I b Four standard
I
I
,! I
,".?,.,;. '
Perimeter = 16 centimetres
.'
,..£,
OJ Draw these rectangles on centimetre squared paper. 19 rt'. ~\tl eV ~ 5°°9 weights which
balance 130 9 are
59 109 209 509 1009
200g
a 8 cm long, 2 cm wide b 6 cm long, 4 cm wide
OJ Write five ways to balance SOg 100g and 109 and
c 6 cm long, Scm wide d 7 cm long, 3 cm wide
using these standard weights. 109 and 109 or 50g
e 10 cm long, 1 cm wide 9 cm long, 2 em 'wide
and 50g and 20g
[]] rn Beside each one, write its area and perimeter. rn Use scales and a plastic bag. and 109, etc.
Weigh out 70g of rice into a bag.
Label the bag. (1/3 a)
Practical: drawing
[]] Copy and complete these torn rectangles.
rectangles on The area of each is given. Find their perimeters. []] Write five ways to balance 70g of rice using the weights shown above.
centimetre squared m Copy and complete. Challenge
"C a Three standard weights which balance SOOg are 20 9 of Plasticine
paper. b L~ a Weigh out 4 lots of
__ g and __ g and -- g.
[g] 12 square centimetres --- b Four standard weights which balance 130g are and roll them
20 square centimetres
__ g and __ g and -- g and -- g.
together to make
a 8cm by 2cm CL --r'"" - ... 80g.
area 16 square d [J CHALLENGE
centimetres Use only balance scales, a 20g weight and Plasticine. b Weigh out 3 lots of
perimeter 20 Work out ways to make lumps of Plasticine which weigh : 20 g, halve one of
15 square centimetres them to make two
centimetres a 80g b SOg c 10g d 40g e 2Sg f Sg
25 square centimetres
109 lumps and join
b 6cm by 4cm am I STEPS 3b:1SI I STEPS 3b:16! 20 9 + 20 9 + 109 to
area 24 square make 50g.
centimetres
e Weigh out 20 9 and
perimeter 20
centimetres 00 []] Open: finding five ways to balance 50g halve it by
using the weights listed in 1: balancing 109
e 6cm by 5cm e 10cm by lcm a For example: 50 g; (20 9 + 20 9 + 109); against 109.
area 30 square area 10 square Perimeter (20 9 + 109 + 109 + 5 9 + 5 g); etc.
centi metres centimetres 16cm Practical: weighing out 70 9 of rice in a bag d Weigh out 2 lots of
perimeter 22 perimeter 22 b [g] and labelling it. (1/3 a) 20 g, combine them
centimetres centimetres Perimeter to make 40g.
18cm 00 Open: finding five ways to balance 70 9 e Halve the 50 9 made
d 7cm by 3cm f qcm by 2cm using the weights listed in 1:
area 21 square area 18 square e For example: in b or combine 20 9
centimetres centimetres Perimeter (50 9 + 20 g); (50 9 + 109 + 5 9 + 5 g); etc. and half of half of
perimeter 20 perimeter 22 16cm 20g.
a Three standard weights which balance
centimetres centimetres d ~ f Halve 20 9 and
Perimeter 500 9 are 200 9 and 200 9 and 100 g. halve one 109 lump
20cm to make 5g.