ADDITION:
Through the use of specific strategies, we are teaching
skills the first graders can use to help them become proficient at adding
numbers (without using their fingers!)
Addition Vocabulary:
addition: to join 2 numbers together
addend: the two parts of an addition problem that make up
the sum; the two numbers that are being combined
plus: the symbol used to denote adding or combining numbers
equals: the same as
sum: the answer to an addition sentence
Count on 1 Strategy: The first graders are learning
how to add 1 to numbers. Through the use of the count on 1 strategy, the
children know to say the next number because they can count by 1's. For
example:2 + 1 is the same as counting up to the next number after 2,
which would be 3.The students have also worked on using number tracks (number
lines) to check to see what the next number would be. We have also
learned "turn-around facts". 1 + 2 is the turn-around fact for
2+ 1. When the greater number is the second addend, we have taught the
children to put the greater number in their heads and count up 1 from that
number.
Count on 2 Strategy: This is very similar to the count
on 1 strategy. Put the greater number in your head, and count up two
numbers. 3 + 2 = 5 since 3 goes in your head and say 2 more numbers (4,
5)For our little mathematicians that are proficient at counting by 2's:4 + 2 =
6 since 6 is the next number when you count even numbers by 2.Count on 3 Strategy:
This is definitely the hardest one so far! Put the greater number in your
head, and count up 3 numbers.4 + 3 = 7 since 4 goes in your head and say 3 more
numbers (5, 6, 7)Some students have figured out that 4 + 3 is the same as 5 +
2!
New Vocabulary:
DOUBLES FACT: a doubles fact has two addends that are the
same. 4 + 4 = 8 is a doubles fact.
A few doubles rhymes to help learn the doubles facts:
1+1=2 Zebras belong in the zoo.
2+2=4 I see friends at the door.
3+3=6 A campfire is made of sticks.
4+4=8 It is time to close the gate.
5+5=10 The farmer has a little red hen.
6+6=12 The shoes were made by the little elves.
7+7=14 Give the crown to the queen.
8+8=16 Will you eat a big green bean?
9+9=18 Yellow and blue make green.
10+10=20 She bought more so she'd have plenty.
0+0=0, Oh!
1+1=2, Oooh!
2+2=4, More!
3+3=6, Kicks!
4+4=8, That's great!
5+5=10, Again!
6+6=12, That's swell!
7+7=14, Let's lean!
8+8=16, You're a queen!
9+9=18, Jelly bean!
10+10=20, That's plenty!
The first graders discovered that all doubles facts make
even sums!
SUBTRACTION:
We are learning how to use strategies to help us be faster
at subtracting numbers.
Subtraction Vocabulary:
subtraction: to take one quantity away from another
difference: the answer to a subtraction sentence
related fact: Subtraction does not have turnaround facts
like addition does. However, they do have related facts. For example: 7 -
1 = 6 and 7 - 6 = 1 are related.
Count on 1 Strategy (otherwise known as count down 1)
When you subtract 1 from a number, you say the number that comes next when you
count backwards by ones. For example:5 - 1 = 4 since 4 is the number that
you say when you count backwards by 1 from 5. You can also think addition with
this strategy. What plus 1 would make 5?We also looked at using a number
line to help find the answer. We discovered that it is easier to go
backwards when you subtract one (5 - 1 = 4). However, when you subtract
using the related fact (5 - 4 = 1), it is easier to use addition and go
forwards on the number line from 4 to get to 5 (only 1 space).
Count on 2 (or countdown 2) and Count on 3 (or countdown 3)
strategies have also been taught.
Count on O: This strategy can also be called subtract
zero or subtract none. For example: 6 - 0 = 6 The first graders
discovered that when you subtract zero, but end up with the number you started with.
The other strategy we learned was called subtract all. For example, 7 - 7
= 0 We discovered that when you subtract all, you will end up with 0 as your
answer.