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Mental Math Day 1

Mental Math Day 1. Basic Addition. Add and subtract the summands to make this easier! 1242 + 998 = ? + 1000 = 1240 + 1000 = 2240. More Basic Addition. 5346 + 445 = ? + 450 = 5341 + 450 = 5741+50 = 5791. -. +. SUMMAND 1. SUMMAND 2. You try it! (all techniques).

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Mental Math Day 1

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  1. Mental MathDay 1

  2. Basic Addition • Add and subtract the summands to make this easier! 1242 + 998 = ? + 1000 = 1240 + 1000 = 2240

  3. More Basic Addition 5346 + 445 = ? + 450 = 5341 + 450 = 5741+50 = 5791 - + SUMMAND 1 SUMMAND 2

  4. You try it! (all techniques) • 87654321+12345678= • 123456789+987654321= • 1+2+3+4+5+6+7+8+9 =(1+9)+(8+2)+(7+3)+(6+4)+5 =10+10+10+10+5=45 • 2+4+6+8+10+12+14+16+18= 99999999 1111111110 2x45=90

  5. Sum all entries - Which is More?

  6. SUM All ENTRIES

  7. Total is 10x55+100x45

  8. Total is 10x55+100x45=550+4500=5000+50=5050

  9. Add up all the numbers in this table (in your head!)

  10. Sum is 55x55 + 55+55=? 55 more

  11. Sum is 55x55 + 2x55=? =(50+5)x(50+5)+2x55 =(50x50)+5x50+50x5+5x5+2x55 So we need the total of • 2500 • 250 • 250 • 25 • 110

  12. Sum is 55x55 + 55=? So we need the total of • 2500 • 250 • 250 • 25 • 110 This is 2500+500+135=3135

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