Basic Facts
Groupings within 100 (multiples of 5’s)
L.O : To become more accurate and faster at this set of basic facts: Groupings within 100 - Multiples of 5
(5’s eg 65 +35)
Understand - Practise - Learn - Know
35 + 65 = 100
65 + 30 = 100
100 - 65 = 35
100 - 35 = 65
Understand:
You know your number bonds to 10, and decades to 100.
So these facts will look similar - just there is a 5 on the end.
5 has been added to 30,
so it is taken off 70,
which becomes 65.
Which is why the sum is still 100
30 + 70 = 100
70 + 30 = 100
100 - 70 = 30
100 - 30 = 70
Decades to 100, family of facts
Groupings within 100 - Multiples of 5
Family of facts
Learn: Adding to 100 using multiples of 10
5 + 95 = 100
15 + 85 = 100
25 + 75 = 100
35 + 65 = 100
45 + 55 = 100
55 + 45 = 100
65 + 35 = 100
75 + 25 = 100
85 + 15 = 100
95 + 5 = 100
You could:
Recite them to yourself
Pop on a screen-castify
Or copy them out on a white board
Or repeat them while bouncing a ball outside.
Or write them out on a Family of Facts △
Laminated sheet.
Or get a set of flashcards and test a friend.
Practise: How fast can you do these?
addend | addend | sum |
95 | | 100 |
35 | 65 | |
25 | | 100 |
| 55 | |
75 | | 100 |
| 5 | 100 |
15 | | 100 |
KNOW: Adding to 100 using multiples of 5 numbers
Basic Facts
Test yourself on these facts using Snappy Maths.
Record your score on the next slide.
You will be tested how many you can get right in 1 minute.
Good luck!
Daily 100 Facts Test Record
Date | Score |
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Are you becoming more accurate? Are you gettingmore correct each time? (every test is 1 minute long)
Play the Memory card game with 2 other friends.
Create pairs that add to 100.
You can have them numbers up for first round then turn them numbers down and play Memory with them.
The person with the most pairs wins.
65 35
25
75
15
85
Practise
Understand: Subtraction to 100 using multiples of 5
100 - 5 = 90
100 - 25 = 75
100 - 35 = 65
100 - 45 = 55
100 - 55 = 45
The opposite of addition is subtraction
If you know one fact, you know and understand 3 others.
15 + 85 = 100 so 100 - 15 = 85
85 + 15 = 100 so 100 - 85 = 15
5 + 95 = 100
15 + 85 = 100
25 + 75 = 100
35 + 65 = 100
45 + 55 = 100
55 + 45 = 100
65 + 35 = 100
75 + 25 = 100
85 + 15 = 100
95 + 5 = 100
Practise: How fast can you do these?
15 + . . = 100 | 45 +. . = 100 |
. . + 95 = 100 | . . + 60 = 100 |
100 - . . = 15 | 100 - . . = 45 |
100 - 95 = . . | 100 - 65 =. . |
25 + . . = 100 | 100 + . . =100 |
. . + 85 = 100 | . . + 5 = 100 |
100 - . . = 25 | 100 - . . = 15 |
Watch the sign!
Is it + OR - ?