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Subtraction Counting Down Draw then number line Write the larger number on the right

77 - 22. Subtraction Counting Down Draw then number line Write the larger number on the right Decide how many tens and ones to jump down by looking at the smaller number in the equation. The number you land on is the difference.

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Subtraction Counting Down Draw then number line Write the larger number on the right

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  1. 77 - 22 Subtraction Counting Down • Draw then number line • Write the larger number on the right • Decide how many tens and ones to jump down by looking at the smaller number in the equation. • The number you land on is the difference. • Make sure your jumps add up to the smaller number in the original equation. • *For Accuracy: Check by writing a related addition fact and branching or decomposing to see if you get the big number in the subtraction equation. 1 + 1 + 10 + 10 = 22 (this is the amount subtracted) 55 56 57 67 77

  2. 77 - 29 Subtraction Counting Up • Draw the number line • Write the smaller number on the left • Write the larger number on the right • Jump up by tens until you are close to the large number • Jump to the final number • Add up all the jumps to find the difference *For Accuracy: Check by writing a related addition fact and branching or decomposing to see if you get the big number in the subtraction equation. +10 +10 +10 +10 +1 +7 29 39 49 59 69 70 77 10+10+10+10+1+7= 48

  3. Using a Hundreds Chart 77-22=___ When the smaller number is decomposed the values are 20 and 2. • Jump down two rows of 10. • Move backwards 2 ones. • The difference is the number they land on. • When using a hundreds chart the student needs to begin at the number that is the greatest. • Then they can go down in value by tens- rows. • Finally go backwards by ones until the difference is reached- spaces.

  4. DecomposingRule: Use this method when the ones place in the larger number can take away the ones place in the smaller number in the equation. 77 – 22 70 + 7 20 + 2 50 + 5 = 55

  5. BranchingRule: Use this method when the ones place in the larger number can take away the ones place in the smaller number in the equation. 77 – 22 50 + 5 = 55

  6. Decomposing with Negative NumbersIf the child has a FIRM GRASP of the concept of simple negative numbers on a number line they can subtract using negative numbers in the ones place. This will create a subtraction problem to find the difference. 72 – 25 70 + 2 20 + 5 50 - 3= 47

  7. Branching with Negative NumbersIf the child has a FIRM GRASP of the concept of simple negative numbers on a number line they can subtract using negative numbers in the ones place. This will create a subtraction problem to find the difference. 72 – 25 50 -3 = 47

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