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Near Doubles I am learning to solve addition problems where the two numbers are easily related to doubles. e.g. 9 + 9 = 18 Or 80 + 80 = 160 Craig has $79 and saves another $81. How much money does he have? 79 + 81 = ? Step 1: Let’s use some notes and coins to represent this question. Step 2: If we move $1 from the $79 to the $80 then both piles will have $80. Step 3: Swap the ten $1 coins for a $10 note and then both groups have $80 80 + 80 = 160 $10 $10 $10 $10 $10 $10 $10 $10 1 1 1 1 1 1 1 1 1 1 $10 $10 $10 $10 $10 $10 $10 $10 1 Kim drove 78km on Monday and 79km on Tuesday. How many kilometres has she driven? 78 + 79 = ? 78 + 79 = …… +2 +1 Step 1: Let’s use our doubles to help us answer this question. Change the question into 80 + 80. This will be much easier to answer. 80 + 80 = 160 Step 2: We added 2 to the 78 and 1 to the 79 (a total of 3). So now we must subtract 3 from our answer of 160. 160 – 3 = 157 Now try these questions on your own. 1) 69 + 71 = ? 140 2) 38 + 38 = ? 76 3) 89 + 92 = ? 181 4) 148 + 252 = ? 400 5) 119 + 119 = ? 238 Click again when you have completed each question and the answer will be displayed. Need some more practise? Try Pg55 of Teacher Tools Addition and Subtraction Book Numeracy resources