Addition & subtraction

• Bonds to tenBonds to ten5 + • = 10
• Partitioning to tenHow many more are needed?3 + • = 8
• Split houses to 10Friends of 10 in the split house7 + 3
• Split houses and teen numbersSplit into two rooms8 − 5
• Partitioning to twentyNumbers above ten are ten and ones10 + • = 15
• Counting back to tenHow many to subtract for ten?15 − • = 10
• Addition within tenStart with the larger number4 + 4
• Counting frame to 10Look at the 5 red and 5 white beads5 + 2
• Counting frame to 20First the full top bar of 1010 + 4
• Bus problems: getting onCount who gets on4 + 3
• Bus problems: getting offCount who gets off8 − 3
• Subtraction within tenThink of addition8 − 3
• Vanishing sums and almost-vanishingEverything or almost everything away15 − 15
• Doubles and halvesUse doubles you know5 + 6
• Addition within twentyAdd to the ten13 + 5
• Subtraction within twentyTake away from the ones17 − 4
• Addition bridging tenMake ten first8 + 7
• Subtraction bridging tenBridge through ten15 − 8
• Jumps of ten and oneJumps of ten and one13 + 10
• Addition within a hundredTens and ones separately30 + 40
• Bonding to the next tenMaking up to a round number95 + • = 100
• Addition bridging tensBridge through the ten64 + 8
• Addition with tens and onesTens first, then ones36 + 47
• Quick methods with 9, 19, 29Calculate with the round number, then adjust92 − 19
• Subtraction with tens and onesTake away the tens first81 − 47
• Addition to a thousandCalculate in round steps340 + 70
• Calculating with 25 and 50Think in quarters and halves450 − 75
• Difference: counting onClose numbers? Count on604 − 598
• Addition with large numbersCounting with zeros4500 + 4500