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Addition 1 1. How many additions to 100 can you write in 1 minute? Use 2-digit numbers. For example, 25 + 75 = 100 or 21 + 79 = 100 100 100 All possible answers (order can be reversed!):10 + 90; 11 + 89; 12 + 88; 13 + 87; 14 + 86; 15 + 85; 16 + 84; 17 + 83; 18 + 82; 19 + 81; 20 + 80; 21 + 79; 22 + 78; 23 + 77; 24 + 76; 25 + 75; 26 + 74; 27 + 73; 28 + 72; 29 + 71; 30 + 70; 31 + 69; 32 + 68; 33 + 67; 34 + 66; 35 + 65; 36 + 64; 37 + 63; 38 + 62; 39 + 61; 40 + 60; 41 + 59; 42 + 58; 43 + 57; 44 + 56; 45 + 55; 46 + 54; 47 + 53; 48 + 52; 49 + 51; 50 + 50. 2. Roll a dice four times (or choose from numbers 1-6 on pieces of paper) and write the digits in this form □□00 + □□00. Find the total. What is the biggest answer you could get with these digits? And the smallest? Have another go. I rolled: 6 2 3 6200 + 3500 = 9700 Largest answer possible 6300 + 5200 = 11,500 Smallest answer possible 2500 + 3600 = 6100 3600 + 3100 = 6700 2500 + 4100 = 6600 6300 + 3100 = 9400 5200 + 4100 = 9300 1300 + 3600 = 4900 1400 + 2500 = 3900 Addition 5 3 6 3 1 2 5 1 4 3. Repeat using this form: □□,000 + □□,000. Largest answer I rolled: Addition possible 43,000 + 25,000 = 43,000 + 52,000 4 2 3 5 = 95,000 68,000 21,000 + 36,000 = 57,000 54,000 + 24,000 = 4 78,000 2 1 3 6 5 4 2 HSNP © Hamilton 2013 62,000 + 31,000 = 93,000 54,000 + 42,000 = 96,000 Simmering Term 1 Smallest answer possible 25,000 + 34,000 = 59,000 13,000 + 26,000 = 39,000 24,000 + 45,000 = 69,000 Page 3 Addition 1 4. Use all the digits from 2 to 9 to make pairs of four-digit numbers. For example, 2345 + 6789 = 913 Find a pair with the biggest possible total, the smallest possible total and a total as close to 8000 as you can. 9753 + 8642 = 18,395 Biggest total 2468 + 3579 = 6047 Smallest total 5649 + 2378 = 8027 Closest to 8000 If you have internet access, try this Play Speedy Grid Challenge at bit.ly/13pRdr7. Try to answer 10 questions in three minutes. You will be given a number. Find 2 numbers in the grid that make this total. How many questions did you answer in 3 turns? Score turn 1: Score turn 2: Score turn 3: ________ ________ ________ This is a computer game. just right too hard 3 How did you find these problems? 1 2 Page 4