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Subtracting integers with number lines. Page 71 MMS grade 7. 7 -5 =2 .draw a yellow arrow to the right from 0 to 7. Then draw a red arrow facing left from 7, stop after 5 jumps.
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Subtracting integers with number lines Page 71 MMS grade 7
7 -5 =2 .draw a yellow arrow to the right from 0 to 7. Then draw a red arrow facing left from 7, stop after 5 jumps.
5 – (-2)=7 think , how many jumps does it take to get from -2 to 5 ? You are measuring the difference between(-2) and 5.
One “cheat” when subtracting is to add the opposite. • 7-5 = Both are positive integers so simply subtract. • 5-(-2)= you are subtracting a negative number so think add the opposite 5+2 = ? • -9 –(-4) You are subtracting a negative number from a negative number. Take the absolute value of each number. • -9 becomes 9 and negative 4 becomes 4. add. • 9+4
Confused ? Try this explaination • http://www.youtube.com/watch?v=RDw3Gq-heTw
Still a little unsure ? Try this.Put a number line on the floor with masking tape. Start at 0 and face in the positive direction. To find (-2)+(+3)= step back 2 steps so you are on -2 on the number line. Now walk ahead three steps.
That, now try subtracting. Start was adding the same way but whenever you see a subtraction sign – it means change direction. So turn around • To find (+1) –(+3) Stand on 0, face positive direction. Walk forward one step. Now turn around and face the opposite direction and walk forward +3 steps.
Let’s try walking on the number and subtracting negative numbers. • (-3)-(-5) =? • Find zero, face to the positive, walk back ward 3 steps ( backward because it is negative 3) you see a subtraction sign so that means turn around, now go backward 5 steps ( move backwards because 5 is negative) • What did you land on ? That is your answer.
Please try the following problems. Use a number line or walk them out. Head up you coil note book page. • Date subtract integers • a) (+7) – (-3) b) (+9) – (-9) • c) (+3) – (-7) d) (+5) – (+12) • e) (-8) – (-10) f) (-11) - (+13) • g) (-15) – (+8) h) (-12) – (-12)