Addition and subtraction answers.pdf - Moree Web

Addition mental strategies – number complementsTwo numbers that add together are called complements.12 and 8 are complements to 20 because 12 + 8 = 2035 and 65 are complements to 100 because 35 + 65 = 1001Loop the complements in each set:a Complementsto 20. There arethree to find.The first onehas been donefor you.7 4 1410 1 610 12 8b Complementsto 50. Thereare eight tofind:26 12 30 2024 38 15 3517 45 5 4033 18 32 102Complete these complement webs. Start with the centre number and subtract.Write your answers in the ovals:50 40 5050 24 30 5050 4070 50–10 –50–26 –20–60 –30a 45 50 –5 50 –25 50 25 b 85 50 –15 100 –90 50 1015– 35 – 15 – 25 – 75–30–20357550 20 80 50253Show how knowing the complements to 20, 50 and 100 makes adding easier. Youmay want to loop the complements first. The first one has been done for you.a 80 + 20 + 15 + 5b 18 + 2 + 30 + 20 + 10 + 10= _____________________________________100 + 20 = 120= _____________________________________20 + 50 + 20 = 90c 25 + 25 + 40 + 30 + 20 + 10 = _____________________________________50 + 40 + 50 + 10 = 150d 15 + 35 + 20 + 30 + 10 + 12 = _____________________________________50 + 50 + 10 + 12 = 122Addition and SubtractionCopyright © 3P LearningE 1SERIESTOPIC1