Math Words and Ideas Addition Combinations Math Words • sum (page 1 of 4) One of your goals in math class this year is to review and practice all the addition combinations up to 10 ! 10. 10 + 10 = 2+7= 7+2= 4+6= 6+4= 3+3 = 5+8= 8+5= Learning Two Combinations at a Time These two problems look different, but they have the same sum. 8 ! 3 3 ! 8 When you know that 8 ! 3 " 11, you also know that 3 ! 8 " 11. You’ve learned two addition combinations! Why do these two problems have the same answer? 7!2"9 2!7"9 16 sixteen Math Words and Ideas Addition Combinations (page 2 of 4) A helpful way to learn addition combinations is to think about one category at a time. Here are some categories you may have seen before. You probably already know many of these combinations. Make 10 Combinations 2 ! 8 " 10 8 ! 2 " 10 3 ! 7 " 10 7 ! 3 " 10 4 ! 6 " 10 6 ! 4 " 10 Doubles Combinations 6 ! 6 " 12 7 ! 7 " 14 8 ! 8 " 16 5 ! 10 " 15 10 ! 5 " 15 6 ! 10 " 16 10 ! 6 " 16 Plus 10 Combinations 4 ! 10 " 14 10 ! 4 " 14 seventeen 17 Math Words and Ideas Addition Combinations (page 3 of 4) Here are some more categories to help you learn more of the addition combinations. Near-Doubles Combinations Some combinations are close to a doubles combination you know. Here are two examples. Doubles minus 1 6!7# 7!6# Doubles plus 1 7!8# 8!7# Think: 7 ! 7 " 1 Think: 7 ! 7 ! 1 !1 "1 7 ! 6 # (7 ! 7) " 1 # 13 7 ! 8 # (7 ! 7) ! 1 # 15 Plus 9 Combinations You can learn some combinations by relating them to a plus 10 combination you know. Here are two examples. 5!9# 9!5# Think: 9 ! 1 ! 4 Think: 10 ! 5 " 1 "1 9 ! 5 # 10 ! 4 # 14 18 eighteen 9 ! 5 # (10 ! 5 ) " 1 # 14 Math Words and Ideas Addition Combinations (page 4 of 4) As you practice all the addition combinations, there will be some that you “just know” and others that you are “working on.” To practice combinations that are difficult for you to remember, think of a combination that you know as a clue to help you. Here are some examples. Gil and Ines have different clues to help them solve 5 ! 7. Gil: I think of 7 ! 7, and then subtract 2. 5 7 ! ! " " 7 5 Clue: 7 + 7 - 2 Ines: First I add 5 ! 5, and then add 2 more. 5 7 ! ! 7 5 " " Clue: 5 + 5 + 2 Do you know these combinations or are you learning them? 5 8 7 !7 !6 !4 nineteen 19
© Copyright 2024 Paperzz