Math

WALT find sale prices

(okay to use a calculator)

E.g. $19.99 divide by 100 x 25

	25% off	So how much do you pay?
$19.99	$5	14.99
$14.99	$4	10.99
$13.98	$3	10.98
$17.45	$4	13.45
$14.89	$4	10.89
$7.99	$2	5.99
$13.90	$3	10.90
$199	$49	150
$250	$62	185
$176	$44	132
$1.99	$0.5	1.49

Number divide by 100 x 45 = 

	45% off	So how much do you pay?
$19.99	$9	10.99
$14.99	$7	7.99
$13.98	$6	7.98
$17.45	$8	945
$14.89	$7	7.89
$7.99	$4	3.99
$13.90	$6	7.90
$199	$90	109
$250	$112	138
$176	$79	97
$1.99	$1	0.99

Converting between decimals and percentages is easy when you know what to look for. Remember that 1.00 = 1 whole = 100% - these things are all the same. So 0.50 will be 50%, 0.30 = 30%, 0.10 is 10%. E.g. using different place value positions 12.87 = 1,287% 4.56 = 456% 1.42 = 142% 0.56 = 56% 0.09 = 9% 0.005 = 0.5% *Remember to check your place value*

Change these decimals into percentages (put it next to the decimal).
Decimal	Percentage	Decimal	Percentage
0.12	12%	0.99	99%
0.76	76%	0.76	76%
0.80	80%	0.34	34%
1.00	100%	0.45	45%
2.00	200%	1.23	123%
5.6	560%	0.99	99%
0.44	44%	1.45	145%
0.32	32%	8.65	865%
0.56	56%	1.45	145%
0.09	9%	3.65	365%
0.07	7%	1.22	122%
1.34	134%	12.09	1209%
0.23	23%	0.06	6%
0.776	776%	0.045	4.5%
0.087	8.7	0.32	32%
0.124	12.4%	0.08	8%
1.579	157.9%	0.3	30%
2.40	240%	0.04	4%
2.04	204%	0.001	0.1%
0.01	1%	0.012	1.2%

To change from percentages to decimals, do the opposite.
Percentage	Decimal	Percentage	Decimal
10%	0.10	66%	0.66
20%	0.20	40%	0.40
15%	0.15	30%	0.30
100%	1.00	%	???
150%	1.50	87%	0.87
200%	2	12%	0.12
165%	1.65	1%	0.01
45%	0.45	90%	0.90
90%	0.90	70%	0.70
80%	0.80	60%	0.60
60%	0.60	54%	0.54
65%	0.65	45%	0.45
55%	0.55	87%	0.87
34%	0.34	23%	0.23
12%	0.12	54%	0.54
5%	0.05	29%	0.29
1%	0.01	12%	0.12
4%	0.04	56%	0.56
2%	0.02	23%	0.23
0.5%	0.50	78%	0.78
98%	0.98	56%	0.56
99.5%	0.995	123%	1.23
120%	1.20	134%	1.34
150%	1.50	165%	1.65

Everyone should be able to find 10% of an amount easily, because there is a place value trick to it. If you are finding harder percentages, there is a formula to use (calculator allowed!) Finding 10% in your head. Pick up the decimal place and move it one spot to the left - E.g. $45.00 - move the decimal - $4.50 -- so 10% of $45 is $4.50

Finding 10% in your head
	10% of that number
$150.00	15.000
$65.00	6.5
$75.00	7.5
$90.00	9.000
$140	14.0
$120	12.0
$125	12.5
$199.99	19.999
$250	25.0
$49.99	4.999
$1,500	150.0
$4,950	495.0

Finding percentages - USE A CALCULATOR FOR THESE. Amount / total x 100 = E.g. 20/35 x 100 = 57%

	= Percentage
14/20	70%
3/15	20%
60/80	75%
45/50	90%
87/90	97%
14/30	47%
65/80	81%
17/35	49%
19/25	76%
17/20	85%
16/27	59%
26/29	90%
15/28	54%
13/29	45%
19/32	59%
27/46	59%
19/70	27%
3/45	7%
18/95	19%
14/65	22%

Word problems
Lucy went for a walk with her family during lockdown. On Monday they walked 2.5km. On Tuesday they walked 4.19km. How far did they walk altogether? 6.69
Mele’s goal was to walk 20km in one week during lockdown. The path from her house to the bottom of Mt Wellington is 1.9km one way. How many times does she need to walk to the mountain and back to reach her goal? 11
There are 30 students in Room 30. Three fifths of them are going to stay home during Level 2. How many are staying home? How many are coming to school? 6 are staying and 24 are going
Miss Ashley estimates that 40% of the year 7/8s will turn up to technology on Thursday. If there are 70 year 7/8s altogether, how many will turn up? 28
Dad bought a 1.5kg bag of flour. He uses 3 cups of flour to make a cake. How much flour is left? (You can express this in kg, percentage or fraction - you choose). 0.6kg
Miss Ashley did a typing test online. The test is to get 10 words spelt accurate and as fast as you can. On Monday she could do it in 12.7 seconds. On Tuesday she could do it in 9.9 seconds. How much faster did she get? 2.8
Two families are having pizza for dinner on the same night. In the first family, Michael, Mariah, Hope, Hevani and their mum and dad and 2 older brothers shared six pizzas equally between them. In the other family, Davlyn, Jairus and Saryah shared three pizzas between them. In which family would you get the most pizza? The first family  will have 1.33 and the second will have 1 each
Miss Ashley is making lots of pancakes. She has 5.5kg of flour left. Each pancake uses 0.275kg of flour. How many pancakes can she make? 5.5 divided by  0.275kg is 20
On speedskills, Tim got 24 questions correct out of 30. What is this as a percentage? 80%
Miss Ashley has $50 for petrol for her car. If petrol is $1.85 per litre, can she get enough petrol to fill up her 30 litre tank? no
Bonus: if she doesn’t have enough, how much more money does she need to fill it up? 5.5