Addition & Subtraction Strategies

Addition Strategies 
Useful for helping your child develop fluency with addition:

Count All: Count all of the objects in both numbers 

(This is just for the beginning to establish the concept of addition)

Count On: Start with the bigger number and count on 

(This is a transitional strategy to get us out of the counting all)

Add 2: Start with the bigger number and skip a number to add by 2 

(5+2 skips over 6 and finishes at 7 on a number line)

Add 3: Use your 'Add 2' strategy and go 1 further 

(Once you know 5+2=7, go 1 more for 5+3 and get 8)

Add 4: Use your 'Add 2' strategy twice 

(If you know 5+2=7, do another skip by jumping over 8 to solve 5+4=9)

Doubles: Adding a number with itself 

(This is quicker and easier than just counting on, and is used heavily for multiplying)

Doubles plus One: Use your doubles facts and add 1 extra 

(In 4+5 think of 5 as 4+1, so 4+5 is 4 doubled [8] plus 1)

Turn-Arounds: You can switch the addends (Used best when adding 5,6,78,8; .If you know 8+2, then you know 2+8)

Add 9: Start by adding 10, then just take 1 away 

(For 8+9 start with 8+10 [18] and take away 1 to get 17)

Add 10: To add 10 you are putting 1 in the tens column 

(7+10 starts with 0 tens,7 ones; We put 1 in the tens column [17])

Make 10: Create a group of 19, then add on 

(For 8+6, think of 6 as 2+4, so 8+6 is 8+2+4 which is just 10 and 4 more, 14)

 

Subtraction Strategies

Useful for helping your child develop fluency with subtraction: 
 

Subtract to 10: Subtract to get back to 10, then subtract the rest 

(12-5 : 12-2 gets you back to 10 then -3 = 7)

Subtract to 10s: Subtract to get back to the nearest ten, then the rest 

(82-5 : 82-2 gets you 80 then -3=77)

Subtract to 100: Subtract to get back to 100, then subtract the rest 

(120-50 : 120-20 get you to 100, then -30 = 70)

Add Up: Use addition to find the difference between numbers 

(17-8 : 8 +2 makes 10 then +7 more for a total of 9 [2+7] )

Partial Differences: Find individual column differences 

(48-36 : Tens [4-3=1] Ones [8-6=2], so answer=12)