Three or more at a time. I am learning to look at the addition and subtraction of three or more numbers to calculate easy combinations first. e.g. 3 + 6 + 7 = ? 3 + 7 = 10 10 + 6 = 16
Angela has $82, Sam has $114 and Julie has $18 Angela has $82, Sam has $114 and Julie has $18. How much do they have in total? 82 + 114 + 18 = ? Step 1: Let’s use some notes and coins to represent this question. Step 2: $82 and $18 can be joined together to make $100. Exchange the ten $1 coins for a $10 note. 82 + 114 + 18 = ? Exchange the ten $10 notes for a $100 note. 82 + 18 + 114 = ? Step 3: Add them together $100 + $114 = $214 $10 $10 $10 $10 1 1 1 $10 1 1 1 1 $10 $10 1 1 1 1 1 $10 1 1 1 1 1 $10 $10 $100 1 1 $100 $10 1 $10 1 1
Anthony has $232. He saves another $19 doing jobs at home but spends $132. How much money does he have? 232 + 19 – 132 = ? Step 1: Let’s use some notes and coins to represent the money he has. Step 3: It’s easy to subtract $132 from $232 (232 – 132 = ?). Let’s do that now. 232 + 19 - 132 = ? Step 4: Add together what’s left. 232 - 132 + 19 = ? $100 + $19 = $119 1 1 1 1 1 $10 1 1 1 $100 $10 $100 $100 $10 1 $10 1 1
Now try these questions on your own. 91 + 13 + 9 = ? 134 + 57 - 34 = ? 214 + 81 + 19 = ? 77 – 20 + 23 = ? 56 – 34 + 44 = ? 113 Click again when you have completed each question and the answer will be displayed. 157 314 80 66 Need some more practise? Try Pg56 of Teacher Tools Addition and Subtraction Book Numeracy resources