Mixed Addition & Subtraction L.O. TO BE ABLE TO WORK OUT MIXED ADDITION AND SUBTRACTION EXPRESSIONS Collect Homework

What must you remember?  You must remember that it is the sign IN FRONT of the number that tells you what to do with that number!  If the sign is plus you must add that number to the rest  If the sign is minus you must take that number away from the rest

You can add and take away in ANY ORDER  Example – 94 To 138 we must add 76 and take away 94 I can add 76 first then take away = – 94 = 120 I can take away 94 first then add – 94 = = 120 FIRST NUMBER We can do the operations in any order but we MUST START WITH THE FIRST NUMBER !!!

Example: 42 –  We must start with 42 but we can add and take away in any order  Notice that we can’t take away 70 first so we must choose a different order here! I can add 51 then take away 3 and = – 3 = – 70 = 20 I can take away 3 first then add 51 and take away = = – 70 = 20

Example: 95 –  We must start with 95 but we can add and take away in any order  Notice that we can’t take away 161 first so we must choose a different order! I can add 75 first then take away 161 and add = – 161 = = 19 I can add 10 first then 75 then take away = = – 161 = 19

Mixed addition & subtraction sums  You MUST ALWAYS start with the FIRST number  To this first number you can then add or take away in any order  The sign IN FRONT of the number tells you what to do with that number

Suggestion..  If you can work the sum in the order that it is given, then do it !  If you can’t, then remember that the sign in front tells you what to do with the number!

Bingo Activity Time

– 8 – 3  = 16  16 – 8 = 8  8 – 3 = 5  If you chose 5  cross it off!

36 –  = 12  = 74  74 – 49 = 25  If you chose 25  cross it off!

361 – – 81  361 – 200 = 161  = 176  176 – 81 = 95  If you chose 95  cross it off!

–  = 137  = 230  230 – 210 = 20  If you chose 20  cross it off!

23 –  = 21  = 25  = 30  If you chose 30  cross it off!

– 78 – 50  = 128  128 – 78 = 50  50 – 50 = 0  If you chose 0  cross it off!

– 11 – 9  = 33  33 – 11 = 22  22 – 9 = 13  If you chose 13  cross it off!

952 – 1010 –  = 1390  = 380  380 – 251 = 129  If you chose 129  cross it off!

– 9 – 3 – 5  = 21  21 – 9 = 12  12 – 3 = 9  9 – 5 = 4  If you chose 4  cross it off!

Find the difference between one hundred and ninety, and eighty-three. Then add on thirty-seven  190 – 83 = 107  = 144  If you chose 144  cross it off!

– 78 – 14  = 175  175 – 78 = 97  97 – 14 = 83  If you chose 83  cross it off!

612 –  612 – 318 = 294  = 513  = 597  If you chose 597  cross it off!

Homework for Tomorrow STP 7 Pg 4 Ex 1c 5,10,15 Pg 7 Ex 1e 5,17,24 Pg 9 Ex 1f 13, 17, 19