How to do 56-7 = () - 1?

How to do 56-7 = () - 1?

56-7=56-6-1=(56-6)-1=50-1

How to do the full page answers of mathematics guidance series 55.56.57 in Volume 2 of grade 6?

55 pages
1、C B A D
2. (78.5%) (1.57) times
3、
(1) (25 + 30) × 20 △ 2 = 550 (m) 550 △ 0.4 = 1375 (trees)
(2) 1.30M = 130 (DM) 130 ／ 30 ≈ 4 (pieces) 90 ／ 3 = 3 (pieces) 4 × 3 = 12 (pieces)
﹙3﹚60×35=2100﹙㎝﹚ 2100÷50=42﹙㎝﹚﹙42+64﹚×2=204﹙㎝﹚=2.04﹙m﹚
﹙4﹚3×4÷5=2.4﹙㎝﹚ 24×9÷2=10.8﹙㎝﹚
56 pages
1、C A B B
2. The first top, the second front, the third side
3、 ﹙1﹚ 20dm²
(2) one, three, one
4. Draw two circles with a radius of one centimeter
The surface area is 18.84 cm and the volume is 6.28 cm and 179;
Page 57
1、﹙1﹚ 120L
﹙2﹚324㎝² 216㎝³
﹙3﹚ 72㎝³ 48㎝³
2. Cm (?) (?) = 10 × 10 cm
3. Volume 28.26 × 2 × 1 / 3 = 18.84 (m ᦉ 179;) bottom area 3.14 × 2 ᦉ 178; = 12.56 (m ᦉ 178;) height 18.84 ᦉ 12.56 = 1.5 (m)
4、8dm=80㎝ 4dm=40㎝ 80×40×5=16000﹙㎝³﹚ 16000÷4＝4000﹙㎝³﹚
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Grade 6 Volume 2
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A two digit number, and the sum of the two digits that the number is transposed into must be a multiple of 11. Do you know why? For example: 12 + 21 = 33, 23 + 32 = 55

Let a two digit number be a and a ten digit number be B,
Then the two digits can be expressed as: 10B + a
The two digits of the digital transposition are: 10A + B
The sum of them is (10b + a) + (10a + b) =. = 11 (a + b)
That is, the number must be a multiple of 11