# Arithmetical Spyglass and Teacher's Assistant: Intended as a Key and Supplement to the Different Works on Arithmetic, for the Use of Schools and Academies

Waterhouse, 1842 - 166 sider

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### Innhold

 Arithmetical Developments Demonstrations c Page 7 to 36 7 Division 14 Problems Rules and Examples 21 Decimal Fractions 27 Proportion e 34 Proportionals Exercises for the class 39 to 57 Partnership 63 Insurance 69
 Annuities 75 Square Root Page 81 Philosophical Problems Multum in parvo 95 Falling Bodies 109 Problems Rules and Examples 122 Problems Rules and Examples From Algebra 141 to 145 to 158

### Populære avsnitt

Side 74 - Compute the interest on the principle to the time of the first payment; if that be one year or more from the time the interest commenced, add it to the principal, and deduct the payment from the sum total. If there be after payments made, compute the interest on the balance due, to the next payment, and then deduct the payment as above ; and in like manner from one payment to another till all the payments are absorbed ; provided the time between one payment and another be one year or more.
Side 88 - ... 5, 7, 9, 11, 13, 15, &c. is an ascending series. ( 15, 13, 11, 9, 7, 5, 3, &c. is a descending series. The numbers which form the series are called the terms of the series. The first and last terms are the extremes, and the other terms are called the means. There are five things in arithmetical progression, any three of which being given, the other two may be found : — 1st.
Side 89 - Divide the difference of the extremes by the number of terms, less 1, and the quotient will be the common difference.
Side 34 - ... when the first is to the third, as the difference between the first and second is to the difference between the second and third, as the numbers 3, 4, 6.
Side 101 - The pulley is a small wheel, movable about its axis by means of a cord, which passes over it. When the axis of a pulley is fixed, the pulley only changes the direction of the power ; if movable pulleys are used, an equilibrium is produced when the power is to the weight as one to the number of ropes applied to them.
Side 75 - If any payments be made of a less sum than the interest arisen at the time of such payment, no interest is to...
Side 37 - There is a certain number which being divided by 7, the quotient resulting multiplied by 3, that product divided by 5, from the quotient 20 being subtracted, and 30 added to the remainder, the half sum shall make 65 ; can yon teli jnethe number?
Side 32 - Therefore, 54 measures b'oth 918 and 1998. It is also the greatest common measure; for, suppose there be a greater — then, since the greater measures 918 and 1998, it also measures the remainder, 162; and since it measures 162 and 918, it also measures the remainder 108; in the same manner it will be found to measure the remainder, 54; that is, the greater measures the less, which is absurd.
Side 154 - C. owes D. \$1400, to be paid in 3 months ; but D. being in want of money, C. pays him at the expiration of 2 months, \$1000; how much longer than 3 months ought C., in equity, to defer the payment of the rest ? Ans.
Side 42 - If 30 men can perform a piece of work in 11 days, how many men will accomplish another piece of work, 4 times as big, in af,fth part of the time ? Ans.